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LICENSE

@@ -0,0 +1,74 @@
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README.md

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+# UniSpeech
+
+This is the official implementation of paper "[UniSpeech: Unified Speech Representation Learning with Labeled and Unlabeled Data](https://arxiv.org/abs/2101.07597)". The implementation mainly based on [fairseq](https://github.com/pytorch/fairseq) codebase.  We release the training recipes on CommonVoice dataset.
+
+## Requirements and Installation
+
+ - Pytorch >= 1.4.0
+ - python version >= 3.6
+ ``` bash
+ cd unispeech
+ pip install soundfile
+ pip install librosa
+ pip install pydub
+ pip install --editable ./
+ ```
+## Data Preparation
+Download pretraining audio data from [here](https://commonvoice.mozilla.org/datasets). (We use the June 2020 release version in our paper). 
+Get the wav list and the transcription for each dataset by run:
+```
+python examples/unispeech/unispeech_manifest.py input_meta_file --dest examples/unispeech/data/LANG 
+```
+
+Then convert the audio files in common voices to 16k HZ using the commond:
+```
+python examples/unispeech/adjust_sample_rate.py --wav-path /path/to/wav/ --dest-path /path/to/16kwav/ --input examples/unispeech/data/LANG/*.tsv --output examples/unispeech/data/LANG/*_16k.tsv
+```
+For the finetuning data, our train/val/test splits are following [this](https://dl.fbaipublicfiles.com/cpc_audio/common_voices_splits.tar.gz).
+The phoneme transcriptions are generated by [phonemizer](https://github.com/bootphon/phonemizer) to convert texts to phonemes. Then we create .id files using different vocabularies. All our pre-processed data as well as the dictionaries can be downloaded from [here]. 
+
+## Pretraining
+
+We give the training examples for large model here.
+### Stage 1. Pretraining UniSpeech with labeled data.
+The following script can be used to pre-train an English model:
+```
+bash examples/unispeech/scripts/one2one_large_pretrain_en1350.sh
+```
+To train a multilingual model:
+```
+bash examples/unispeech/scripts/multilingual_large_pretrain.sh
+```
+
+### Stage 2. Continue pre-training with low-resource unlabeled data. (Optional)
+After stage 1, you can continue pre-training the UniSpeech model with only contrastive loss:
+```
+bash examples/unispeech/scripts/continue_pretran.sh
+```
+
+### Stage 3. Finetuning with low-resource labeled data.
+Finally, fint-tune the model with 1 hour labeled data.
+For multilingual models, you can choose to use separate vocabulary (examples/unispeech/data/en/vocab_sep.json) or shared vocabulary (examples/unispeech/data/en/vocab_share.json)
+```
+bash examples/unispeech/scripts/finetune.sh
+```
+
+### Models
+We release our pre-trained English large model and multilingual large model in stage 1 at [here]. You can finetune the model to get the reported results in our paper.
+

config/config.yaml

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+# @package _group_
+common:
+    no_progress_bar: false
+    log_interval: 100
+    log_format: null
+    tensorboard_logdir: null
+    seed: 1
+    cpu: false
+    tpu: false
+    bf16: false
+    fp16: false
+    memory_efficient_fp16: false
+    memory_efficient_bf16: false
+    fp16_no_flatten_grads: false
+    fp16_init_scale: 128
+    fp16_scale_window: null
+    fp16_scale_tolerance: 0.0
+    min_loss_scale: 1.0e-4
+    threshold_loss_scale: null
+    user_dir: null
+    empty_cache_freq: 0
+    all_gather_list_size: 16384
+    model_parallel_size: 1
+    quantization_config_path: null
+    profile: false
+distributed_training:
+    distributed_rank: 0
+    distributed_backend: "nccl"
+    distributed_init_method: null
+    distributed_port: -1
+    device_id: 0
+    local_rank: 0
+    distributed_no_spawn: false
+    ddp_backend: "c10d"
+    bucket_cap_mb: 25
+    fix_batches_to_gpus: false
+    find_unused_parameters: false
+    fast_stat_sync: false
+    broadcast_buffers: false
+    distributed_wrapper: "DDP"
+    slowmo_momentum: null
+    slowmo_algorithm: "LocalSGD"
+    localsgd_frequency: 3
+dataset:
+    num_workers: 1
+    skip_invalid_size_inputs_valid_test: false
+    max_tokens: null
+    batch_size: null
+    required_batch_size_multiple: 8
+    dataset_impl: null
+    data_buffer_size: 10
+    train_subset: "train"
+    valid_subset: "valid"
+    validate_interval: 1
+    fixed_validation_seed: null
+    disable_validation: false
+    curriculum: 0
+    gen_subset: "test"
+    num_shards: 1
+    shard_id: 0
+    max_tokens_valid: ${dataset.max_tokens}
+    batch_size_valid: ${dataset.batch_size}
+optimization:
+    max_epoch: 0
+    max_update: 0
+    clip_norm: 25.0
+    sentence_avg: false
+    update_freq: [ 1 ]
+    lr: [ 0.25 ]
+    min_lr: -1.0
+    use_bmuf: false
+checkpoint:
+    save_dir: "checkpoints"
+    restore_file: "checkpoint_last.pt"
+    reset_dataloader: false
+    reset_lr_scheduler: false
+    reset_meters: false
+    reset_optimizer: false
+    optimizer_overrides: "{}"
+    save_interval: 1
+    save_interval_updates: 0
+    keep_interval_updates: -1
+    keep_last_epochs: -1
+    keep_best_checkpoints: -1
+    no_save: false
+    no_epoch_checkpoints: false
+    no_last_checkpoints: false
+    no_save_optimizer_state: false
+    best_checkpoint_metric: "loss"
+    maximize_best_checkpoint_metric: false
+    patience: -1
+    checkpoint_suffix: ""
+bmuf:
+    block_lr: 1
+    block_momentum: 0.875
+    global_sync_iter: 50
+    warmup_iterations: 500
+    use_nbm: false
+    average_sync: false
+defaults:
+    - task: language_modeling
+    - model: null
+    - criterion: null
+    - optimizer: null
+    - lr_scheduler: null
+    - bpe: null
+    - tokenizer: null
+    - scoring: null
+    - generation: null
+    - common_eval: null
+    - eval_lm: null

config/criterion/adaptive_loss.yaml

@@ -0,0 +1,3 @@
+# @package _group_
+sentence_avg: ${optimization.sentence_avg}
+ddp_backend: ${distributed_training.ddp_backend}

config/criterion/cross_entropy.yaml

@@ -0,0 +1,2 @@
+# @package _group_
+sentence_avg: ${optimization.sentence_avg}

config/lr_scheduler/cosine.yaml

@@ -0,0 +1,7 @@
+# @package _group_
+warmup_updates: 0
+warmup_init_lr: -1
+max_lr: 1.0
+t_mult: 1.0
+lr_period_updates: -1
+lr_shrink: 0.1

config/lr_scheduler/inverse_sqrt.yaml

@@ -0,0 +1,3 @@
+# @package _group_
+warmup_updates: 4000
+warmup_init_lr: -1

config/model/transformer_lm.yaml

@@ -0,0 +1,36 @@
+# @package _group_
+activation_fn: "relu"
+dropout: 0.1
+attention_dropout: 0.0
+activation_dropout: 0.0
+relu_dropout: 0.0
+decoder_embed_dim: 512
+decoder_output_dim: 512
+decoder_input_dim: 512
+decoder_ffn_embed_dim: 2048
+decoder_layers: 6
+decoder_attention_heads: 8
+decoder_normalize_before: true
+no_decoder_final_norm: false
+adaptive_softmax_cutoff: null
+adaptive_softmax_dropout: 0
+adaptive_softmax_factor: 4
+no_token_positional_embeddings: false
+share_decoder_input_output_embed: false
+character_embeddings: false
+character_filters: "[(1, 64), (2, 128), (3, 192), (4, 256), (5, 256), (6, 256), (7, 256)]"
+character_embedding_dim: 4
+char_embedder_highway_layers: 2
+adaptive_input: false
+adaptive_input_factor: 4
+adaptive_input_cutoff: null
+tie_adaptive_weights: false
+tie_adaptive_proj: false
+decoder_learned_pos: false
+decoder_layerdrop: 0
+decoder_layers_to_keep: null
+layernorm_embedding: false
+no_scale_embedding: false
+quant_noise_pq: 0
+quant_noise_pq_block_size: 8
+quant_noise_scalar: 0

config/model/transformer_lm_baevski_gbw.yaml

@@ -0,0 +1,36 @@
+# @package _group_
+activation_fn: "relu"
+dropout: 0.1
+attention_dropout: 0.1
+activation_dropout: 0.0
+relu_dropout: 0.0
+decoder_embed_dim: 512
+decoder_output_dim: 512
+decoder_input_dim: 512
+decoder_ffn_embed_dim: 4096
+decoder_layers: 12
+decoder_attention_heads: 16
+decoder_normalize_before: true
+no_decoder_final_norm: true
+adaptive_softmax_cutoff: null
+adaptive_softmax_dropout: 0
+adaptive_softmax_factor: 4
+no_token_positional_embeddings: false
+share_decoder_input_output_embed: false
+character_embeddings: false
+character_filters: "[(1, 64), (2, 128), (3, 192), (4, 256), (5, 256), (6, 256), (7, 256)]"
+character_embedding_dim: 4
+char_embedder_highway_layers: 2
+adaptive_input: false
+adaptive_input_factor: 4
+adaptive_input_cutoff: null
+tie_adaptive_weights: false
+tie_adaptive_proj: false
+decoder_learned_pos: false
+decoder_layerdrop: 0
+decoder_layers_to_keep: null
+layernorm_embedding: false
+no_scale_embedding: false
+quant_noise_pq: 0
+quant_noise_pq_block_size: 8
+quant_noise_scalar: 0

config/model/transformer_lm_baevski_wiki103.yaml

@@ -0,0 +1,36 @@
+# @package _group_
+activation_fn: "relu"
+dropout: 0.3
+attention_dropout: 0.1
+activation_dropout: 0.1
+relu_dropout: 0.1
+decoder_embed_dim: 1024
+decoder_output_dim: 1024
+decoder_input_dim: 1024
+decoder_ffn_embed_dim: 4096
+decoder_layers: 16
+decoder_attention_heads: 8
+decoder_normalize_before: true
+no_decoder_final_norm: true
+adaptive_softmax_cutoff: "20000,60000"
+adaptive_softmax_dropout: 0.2
+adaptive_softmax_factor: 4
+no_token_positional_embeddings: false
+share_decoder_input_output_embed: false
+character_embeddings: false
+character_filters: "[(1, 64), (2, 128), (3, 192), (4, 256), (5, 256), (6, 256), (7, 256)]"
+character_embedding_dim: 4
+char_embedder_highway_layers: 2
+adaptive_input: true
+adaptive_input_factor: 4
+adaptive_input_cutoff: "20000,60000"
+tie_adaptive_weights: true
+tie_adaptive_proj: true
+decoder_learned_pos: false
+decoder_layerdrop: 0
+decoder_layers_to_keep: null
+layernorm_embedding: false
+no_scale_embedding: false
+quant_noise_pq: 0
+quant_noise_pq_block_size: 8
+quant_noise_scalar: 0

config/model/transformer_lm_big.yaml

@@ -0,0 +1,36 @@
+# @package _group_
+activation_fn: "relu"
+dropout: 0.1
+attention_dropout: 0.0
+activation_dropout: 0.0
+relu_dropout: 0.0
+decoder_embed_dim: 1024
+decoder_output_dim: 1024
+decoder_input_dim: 1024
+decoder_ffn_embed_dim: 4096
+decoder_layers: 12
+decoder_attention_heads: 16
+decoder_normalize_before: true
+no_decoder_final_norm: false
+adaptive_softmax_cutoff: null
+adaptive_softmax_dropout: 0
+adaptive_softmax_factor: 4
+no_token_positional_embeddings: false
+share_decoder_input_output_embed: false
+character_embeddings: false
+character_filters: "[(1, 64), (2, 128), (3, 192), (4, 256), (5, 256), (6, 256), (7, 256)]"
+character_embedding_dim: 4
+char_embedder_highway_layers: 2
+adaptive_input: false
+adaptive_input_factor: 4
+adaptive_input_cutoff: null
+tie_adaptive_weights: false
+tie_adaptive_proj: false
+decoder_learned_pos: false
+decoder_layerdrop: 0
+decoder_layers_to_keep: null
+layernorm_embedding: false
+no_scale_embedding: false
+quant_noise_pq: 0
+quant_noise_pq_block_size: 8
+quant_noise_scalar: 0

config/model/transformer_lm_gbw.yaml

@@ -0,0 +1,36 @@
+# @package _group_
+activation_fn: "relu"
+dropout: 0.1
+attention_dropout: 0.1
+activation_dropout: 0.0
+relu_dropout: 0.0
+decoder_embed_dim: 512
+decoder_output_dim: 512
+decoder_input_dim: 512
+decoder_ffn_embed_dim: 4096
+decoder_layers: 12
+decoder_attention_heads: 16
+decoder_normalize_before: true
+no_decoder_final_norm: true
+adaptive_softmax_cutoff: null
+adaptive_softmax_dropout: 0
+adaptive_softmax_factor: 4
+no_token_positional_embeddings: false
+share_decoder_input_output_embed: false
+character_embeddings: false
+character_filters: "[(1, 64), (2, 128), (3, 192), (4, 256), (5, 256), (6, 256), (7, 256)]"
+character_embedding_dim: 4
+char_embedder_highway_layers: 2
+adaptive_input: false
+adaptive_input_factor: 4
+adaptive_input_cutoff: null
+tie_adaptive_weights: false
+tie_adaptive_proj: false
+decoder_learned_pos: false
+decoder_layerdrop: 0
+decoder_layers_to_keep: null
+layernorm_embedding: false
+no_scale_embedding: false
+quant_noise_pq: 0
+quant_noise_pq_block_size: 8
+quant_noise_scalar: 0

config/model/transformer_lm_gpt.yaml

@@ -0,0 +1,36 @@
+# @package _group_
+activation_fn: "gelu"
+dropout: 0.1
+attention_dropout: 0.1
+activation_dropout: 0.0
+relu_dropout: 0.0
+decoder_embed_dim: 768
+decoder_output_dim: 768
+decoder_input_dim: 768
+decoder_ffn_embed_dim: 3072
+decoder_layers: 12
+decoder_attention_heads: 12
+decoder_normalize_before: true
+no_decoder_final_norm: false
+adaptive_softmax_cutoff: null
+adaptive_softmax_dropout: 0
+adaptive_softmax_factor: 4
+no_token_positional_embeddings: false
+share_decoder_input_output_embed: false
+character_embeddings: false
+character_filters: "[(1, 64), (2, 128), (3, 192), (4, 256), (5, 256), (6, 256), (7, 256)]"
+character_embedding_dim: 4
+char_embedder_highway_layers: 2
+adaptive_input: false
+adaptive_input_factor: 4
+adaptive_input_cutoff: null
+tie_adaptive_weights: false
+tie_adaptive_proj: false
+decoder_learned_pos: false
+decoder_layerdrop: 0
+decoder_layers_to_keep: null
+layernorm_embedding: false
+no_scale_embedding: false
+quant_noise_pq: 0
+quant_noise_pq_block_size: 8
+quant_noise_scalar: 0

config/model/transformer_lm_gpt2_big.yaml

@@ -0,0 +1,36 @@
+# @package _group_
+activation_fn: "gelu"
+dropout: 0.1
+attention_dropout: 0.1
+activation_dropout: 0.0
+relu_dropout: 0.0
+decoder_embed_dim: 1600
+decoder_output_dim: 1600
+decoder_input_dim: 1600
+decoder_ffn_embed_dim: 6400
+decoder_layers: 48
+decoder_attention_heads: 25
+decoder_normalize_before: true
+no_decoder_final_norm: false
+adaptive_softmax_cutoff: null
+adaptive_softmax_dropout: 0
+adaptive_softmax_factor: 4
+no_token_positional_embeddings: false
+share_decoder_input_output_embed: false
+character_embeddings: false
+character_filters: "[(1, 64), (2, 128), (3, 192), (4, 256), (5, 256), (6, 256), (7, 256)]"
+character_embedding_dim: 4
+char_embedder_highway_layers: 2
+adaptive_input: false
+adaptive_input_factor: 4
+adaptive_input_cutoff: null
+tie_adaptive_weights: false
+tie_adaptive_proj: false
+decoder_learned_pos: false
+decoder_layerdrop: 0
+decoder_layers_to_keep: null
+layernorm_embedding: false
+no_scale_embedding: false
+quant_noise_pq: 0
+quant_noise_pq_block_size: 8
+quant_noise_scalar: 0

config/model/transformer_lm_gpt2_medium.yaml

@@ -0,0 +1,36 @@
+# @package _group_
+activation_fn: "gelu"
+dropout: 0.1
+attention_dropout: 0.1
+activation_dropout: 0.0
+relu_dropout: 0.0
+decoder_embed_dim: 1280
+decoder_output_dim: 1280
+decoder_input_dim: 1280
+decoder_ffn_embed_dim: 5120
+decoder_layers: 36
+decoder_attention_heads: 20
+decoder_normalize_before: true
+no_decoder_final_norm: false
+adaptive_softmax_cutoff: null
+adaptive_softmax_dropout: 0
+adaptive_softmax_factor: 4
+no_token_positional_embeddings: false
+share_decoder_input_output_embed: false
+character_embeddings: false
+character_filters: "[(1, 64), (2, 128), (3, 192), (4, 256), (5, 256), (6, 256), (7, 256)]"
+character_embedding_dim: 4
+char_embedder_highway_layers: 2
+adaptive_input: false
+adaptive_input_factor: 4
+adaptive_input_cutoff: null
+tie_adaptive_weights: false
+tie_adaptive_proj: false
+decoder_learned_pos: false
+decoder_layerdrop: 0
+decoder_layers_to_keep: null
+layernorm_embedding: false
+no_scale_embedding: false
+quant_noise_pq: 0
+quant_noise_pq_block_size: 8
+quant_noise_scalar: 0

config/model/transformer_lm_gpt2_small.yaml

@@ -0,0 +1,36 @@
+# @package _group_
+activation_fn: "gelu"
+dropout: 0.1
+attention_dropout: 0.1
+activation_dropout: 0.0
+relu_dropout: 0.0
+decoder_embed_dim: 1024
+decoder_output_dim: 1024
+decoder_input_dim: 1024
+decoder_ffn_embed_dim: 4096
+decoder_layers: 24
+decoder_attention_heads: 16
+decoder_normalize_before: true
+no_decoder_final_norm: false
+adaptive_softmax_cutoff: null
+adaptive_softmax_dropout: 0
+adaptive_softmax_factor: 4
+no_token_positional_embeddings: false
+share_decoder_input_output_embed: false
+character_embeddings: false
+character_filters: "[(1, 64), (2, 128), (3, 192), (4, 256), (5, 256), (6, 256), (7, 256)]"
+character_embedding_dim: 4
+char_embedder_highway_layers: 2
+adaptive_input: false
+adaptive_input_factor: 4
+adaptive_input_cutoff: null
+tie_adaptive_weights: false
+tie_adaptive_proj: false
+decoder_learned_pos: false
+decoder_layerdrop: 0
+decoder_layers_to_keep: null
+layernorm_embedding: false
+no_scale_embedding: false
+quant_noise_pq: 0
+quant_noise_pq_block_size: 8
+quant_noise_scalar: 0

config/model/transformer_lm_wiki103.yaml

@@ -0,0 +1,36 @@
+# @package _group_
+activation_fn: "relu"
+dropout: 0.3
+attention_dropout: 0.1
+activation_dropout: 0.1
+relu_dropout: 0.1
+decoder_embed_dim: 1024
+decoder_output_dim: 1024
+decoder_input_dim: 1024
+decoder_ffn_embed_dim: 4096
+decoder_layers: 16
+decoder_attention_heads: 8
+decoder_normalize_before: true
+no_decoder_final_norm: true
+adaptive_softmax_cutoff: "20000,60000"
+adaptive_softmax_dropout: 0.2
+adaptive_softmax_factor: 4
+no_token_positional_embeddings: false
+share_decoder_input_output_embed: false
+character_embeddings: false
+character_filters: "[(1, 64), (2, 128), (3, 192), (4, 256), (5, 256), (6, 256), (7, 256)]"
+character_embedding_dim: 4
+char_embedder_highway_layers: 2
+adaptive_input: true
+adaptive_input_factor: 4
+adaptive_input_cutoff: "20000,60000"
+tie_adaptive_weights: true
+tie_adaptive_proj: true
+decoder_learned_pos: false
+decoder_layerdrop: 0
+decoder_layers_to_keep: null
+layernorm_embedding: false
+no_scale_embedding: false
+quant_noise_pq: 0
+quant_noise_pq_block_size: 8
+quant_noise_scalar: 0

config/optimizer/adam.yaml

@@ -0,0 +1,5 @@
+# @package _group_
+adam_betas: "(0.9, 0.999)"
+adam_eps: 1.0e-8
+weight_decay: 0
+use_old_adam: false

config/optimizer/nag.yaml

@@ -0,0 +1,3 @@
+# @package _group_
+momentum: 0.99
+weight_decay: 0.0

config/task/language_modeling.yaml

@@ -0,0 +1,10 @@
+# @package _group_
+data: ???
+sample_break_mode: "none"
+tokens_per_sample: 1024
+output_dictionary_size: -1
+self_target: false
+future_target: false
+past_target: false
+add_bos_token: false
+max_target_positions: null

examples/.gitignore

@@ -0,0 +1,2 @@
+!*/*.sh
+!*/*.md

examples/__init__.py

@@ -0,0 +1,6 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from fairseq import __version__  # noqa

examples/speech_recognition/README.md

@@ -0,0 +1,106 @@
+# Speech Recognition
+`examples/speech_recognition` is implementing ASR task in Fairseq, along with needed features, datasets, models and loss functions to train and infer model described in [Transformers with convolutional context for ASR (Abdelrahman Mohamed et al., 2019)](https://arxiv.org/abs/1904.11660).
+
+
+## Additional dependencies
+On top of main fairseq dependencies there are couple more additional requirements.
+
+1) Please follow the instructions to install [torchaudio](https://github.com/pytorch/audio). This is required to compute audio fbank features.
+2) [Sclite](http://www1.icsi.berkeley.edu/Speech/docs/sctk-1.2/sclite.htm#sclite_name_0) is used to measure WER. Sclite can be downloaded and installed from source from sctk package [here](http://www.openslr.org/4/). Training and inference doesn't require Sclite dependency.
+3) [sentencepiece](https://github.com/google/sentencepiece) is required in order to create dataset with word-piece targets.
+
+## Preparing librispeech data
+```
+./examples/speech_recognition/datasets/prepare-librispeech.sh $DIR_TO_SAVE_RAW_DATA $DIR_FOR_PREPROCESSED_DATA
+```
+
+## Training librispeech data
+```
+python train.py $DIR_FOR_PREPROCESSED_DATA --save-dir $MODEL_PATH --max-epoch 80 --task speech_recognition --arch vggtransformer_2 --optimizer adadelta --lr 1.0 --adadelta-eps 1e-8 --adadelta-rho 0.95 --clip-norm 10.0  --max-tokens 5000 --log-format json --log-interval 1 --criterion cross_entropy_acc --user-dir examples/speech_recognition/
+```
+
+## Inference for librispeech
+`$SET` can be `test_clean` or `test_other`
+Any checkpoint in `$MODEL_PATH` can be selected. In this example we are working with `checkpoint_last.pt`
+```
+python examples/speech_recognition/infer.py $DIR_FOR_PREPROCESSED_DATA --task speech_recognition --max-tokens 25000 --nbest 1 --path $MODEL_PATH/checkpoint_last.pt --beam 20 --results-path $RES_DIR --batch-size 40 --gen-subset $SET --user-dir examples/speech_recognition/
+```
+
+## Inference for librispeech
+```
+sclite -r ${RES_DIR}/ref.word-checkpoint_last.pt-${SET}.txt -h ${RES_DIR}/hypo.word-checkpoint_last.pt-${SET}.txt -i rm -o all stdout > $RES_REPORT
+```
+`Sum/Avg` row from first table of the report has WER
+
+## Using wav2letter components
+[wav2letter](https://github.com/facebookresearch/wav2letter) now has integration with fairseq. Currently this includes:
+
+* AutoSegmentationCriterion (ASG)
+* wav2letter-style Conv/GLU model
+* wav2letter's beam search decoder
+
+To use these, follow the instructions on [this page](https://github.com/facebookresearch/wav2letter/tree/master/bindings/python) to install python bindings. Please note that python bindings are for a *subset* of wav2letter and don't require its full dependencies (notably, `flashlight` and `ArrayFire` are *not* required).
+
+To quickly summarize the instructions: first, install [CUDA](https://developer.nvidia.com/cuda-downloads). Then follow these steps:
+```
+# additional prerequisites - use equivalents for your distro
+sudo apt-get install build-essential cmake libatlas-base-dev libfftw3-dev liblzma-dev libbz2-dev libzstd-dev
+# install KenLM from source
+git clone https://github.com/kpu/kenlm.git
+cd kenlm
+mkdir -p build && cd build
+cmake .. -DCMAKE_BUILD_TYPE=Release -DCMAKE_POSITION_INDEPENDENT_CODE=ON
+make -j16
+cd ..
+export KENLM_ROOT_DIR=$(pwd)
+cd ..
+# install wav2letter python bindings
+git clone https://github.com/facebookresearch/wav2letter.git
+cd wav2letter/bindings/python
+# make sure your python environment is active at this point
+pip install torch packaging
+pip install -e .
+# try some examples to verify installation succeeded
+python ./examples/criterion_example.py
+python ./examples/decoder_example.py ../../src/decoder/test
+python ./examples/feature_example.py ../../src/feature/test/data
+```
+
+## Training librispeech data (wav2letter style, Conv/GLU + ASG loss)
+Training command:
+```
+python train.py $DIR_FOR_PREPROCESSED_DATA --save-dir $MODEL_PATH --max-epoch 100 --task speech_recognition --arch w2l_conv_glu_enc --batch-size 4 --optimizer sgd --lr 0.3,0.8 --momentum 0.8 --clip-norm 0.2 --max-tokens 50000 --log-format json --log-interval 100 --num-workers 0 --sentence-avg --criterion asg_loss --asg-transitions-init 5 --max-replabel 2 --linseg-updates 8789 --user-dir examples/speech_recognition
+```
+
+Note that ASG loss currently doesn't do well with word-pieces. You should prepare a dataset with character targets by setting `nbpe=31` in `prepare-librispeech.sh`.
+
+## Inference for librispeech (wav2letter decoder, n-gram LM)
+Inference command:
+```
+python examples/speech_recognition/infer.py $DIR_FOR_PREPROCESSED_DATA --task speech_recognition --seed 1 --nbest 1 --path $MODEL_PATH/checkpoint_last.pt --gen-subset $SET --results-path $RES_DIR --w2l-decoder kenlm --kenlm-model $KENLM_MODEL_PATH --lexicon $LEXICON_PATH --beam 200 --beam-threshold 15 --lm-weight 1.5 --word-score 1.5 --sil-weight -0.3 --criterion asg_loss --max-replabel 2 --user-dir examples/speech_recognition
+```
+
+`$KENLM_MODEL_PATH` should be a standard n-gram language model file. `$LEXICON_PATH` should be a wav2letter-style lexicon (list of known words and their spellings). For ASG inference, a lexicon line should look like this (note the repetition labels):
+```
+doorbell  D O 1 R B E L 1 ▁
+```
+For CTC inference with word-pieces, repetition labels are not used and the lexicon should have most common spellings for each word (one can use sentencepiece's `NBestEncodeAsPieces` for this):
+```
+doorbell  ▁DOOR BE LL
+doorbell  ▁DOOR B E LL
+doorbell  ▁DO OR BE LL
+doorbell  ▁DOOR B EL L
+doorbell  ▁DOOR BE L L
+doorbell  ▁DO OR B E LL
+doorbell  ▁DOOR B E L L
+doorbell  ▁DO OR B EL L
+doorbell  ▁DO O R BE LL
+doorbell  ▁DO OR BE L L
+```
+Lowercase vs. uppercase matters: the *word* should match the case of the n-gram language model (i.e. `$KENLM_MODEL_PATH`), while the *spelling* should match the case of the token dictionary (i.e. `$DIR_FOR_PREPROCESSED_DATA/dict.txt`).
+
+## Inference for librispeech (wav2letter decoder, viterbi only)
+Inference command:
+```
+python examples/speech_recognition/infer.py $DIR_FOR_PREPROCESSED_DATA --task speech_recognition --seed 1 --nbest 1 --path $MODEL_PATH/checkpoint_last.pt --gen-subset $SET --results-path $RES_DIR --w2l-decoder viterbi --criterion asg_loss --max-replabel 2 --user-dir examples/speech_recognition
+```

examples/speech_recognition/__init__.py

@@ -0,0 +1 @@
+from . import criterions, models, tasks  # noqa

examples/speech_recognition/criterions/ASG_loss.py

@@ -0,0 +1,170 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import torch
+from examples.speech_recognition.data.replabels import pack_replabels
+from fairseq import utils
+from fairseq.criterions import FairseqCriterion, register_criterion
+
+
+@register_criterion("asg_loss")
+class ASGCriterion(FairseqCriterion):
+    @staticmethod
+    def add_args(parser):
+        group = parser.add_argument_group("ASG Loss")
+        group.add_argument(
+            "--asg-transitions-init",
+            help="initial diagonal value of transition matrix",
+            type=float,
+            default=0.0,
+        )
+        group.add_argument(
+            "--max-replabel", help="maximum # of replabels", type=int, default=2
+        )
+        group.add_argument(
+            "--linseg-updates",
+            help="# of training updates to use LinSeg initialization",
+            type=int,
+            default=0,
+        )
+        group.add_argument(
+            "--hide-linseg-messages",
+            help="hide messages about LinSeg initialization",
+            action="store_true",
+        )
+
+    def __init__(
+        self,
+        task,
+        silence_token,
+        asg_transitions_init,
+        max_replabel,
+        linseg_updates,
+        hide_linseg_messages,
+    ):
+        from wav2letter.criterion import ASGLoss, CriterionScaleMode
+
+        super().__init__(task)
+        self.tgt_dict = task.target_dictionary
+        self.eos = self.tgt_dict.eos()
+        self.silence = (
+            self.tgt_dict.index(silence_token)
+            if silence_token in self.tgt_dict
+            else None
+        )
+        self.max_replabel = max_replabel
+
+        num_labels = len(self.tgt_dict)
+        self.asg = ASGLoss(num_labels, scale_mode=CriterionScaleMode.TARGET_SZ_SQRT)
+        self.asg.trans = torch.nn.Parameter(
+            asg_transitions_init * torch.eye(num_labels), requires_grad=True
+        )
+
+        self.linseg_progress = torch.nn.Parameter(
+            torch.tensor([0], dtype=torch.int), requires_grad=False
+        )
+        self.linseg_maximum = linseg_updates
+        self.linseg_message_state = "none" if hide_linseg_messages else "start"
+
+    @classmethod
+    def build_criterion(cls, args, task):
+        return cls(
+            task,
+            args.silence_token,
+            args.asg_transitions_init,
+            args.max_replabel,
+            args.linseg_updates,
+            args.hide_linseg_messages,
+        )
+
+    def linseg_step(self):
+        if not self.training:
+            return False
+        if self.linseg_progress.item() < self.linseg_maximum:
+            if self.linseg_message_state == "start":
+                print("| using LinSeg to initialize ASG")
+                self.linseg_message_state = "finish"
+            self.linseg_progress.add_(1)
+            return True
+        elif self.linseg_message_state == "finish":
+            print("| finished LinSeg initialization")
+            self.linseg_message_state = "none"
+        return False
+
+    def replace_eos_with_silence(self, tgt):
+        if tgt[-1] != self.eos:
+            return tgt
+        elif self.silence is None or (len(tgt) > 1 and tgt[-2] == self.silence):
+            return tgt[:-1]
+        else:
+            return tgt[:-1] + [self.silence]
+
+    def forward(self, model, sample, reduce=True):
+        """Compute the loss for the given sample.
+
+        Returns a tuple with three elements:
+        1) the loss
+        2) the sample size, which is used as the denominator for the gradient
+        3) logging outputs to display while training
+        """
+
+        net_output = model(**sample["net_input"])
+        emissions = net_output["encoder_out"].transpose(0, 1).contiguous()
+        B = emissions.size(0)
+        T = emissions.size(1)
+        device = emissions.device
+
+        target = torch.IntTensor(B, T)
+        target_size = torch.IntTensor(B)
+        using_linseg = self.linseg_step()
+
+        for b in range(B):
+            initial_target_size = sample["target_lengths"][b].item()
+            if initial_target_size == 0:
+                raise ValueError("target size cannot be zero")
+
+            tgt = sample["target"][b, :initial_target_size].tolist()
+            tgt = self.replace_eos_with_silence(tgt)
+            tgt = pack_replabels(tgt, self.tgt_dict, self.max_replabel)
+            tgt = tgt[:T]
+
+            if using_linseg:
+                tgt = [tgt[t * len(tgt) // T] for t in range(T)]
+
+            target[b][: len(tgt)] = torch.IntTensor(tgt)
+            target_size[b] = len(tgt)
+
+        loss = self.asg.forward(emissions, target.to(device), target_size.to(device))
+
+        if reduce:
+            loss = torch.sum(loss)
+
+        sample_size = (
+            sample["target"].size(0) if self.args.sentence_avg else sample["ntokens"]
+        )
+        logging_output = {
+            "loss": utils.item(loss.data) if reduce else loss.data,
+            "ntokens": sample["ntokens"],
+            "nsentences": sample["target"].size(0),
+            "sample_size": sample_size,
+        }
+        return loss, sample_size, logging_output
+
+    @staticmethod
+    def aggregate_logging_outputs(logging_outputs):
+        """Aggregate logging outputs from data parallel training."""
+        loss_sum = sum(log.get("loss", 0) for log in logging_outputs)
+        ntokens = sum(log.get("ntokens", 0) for log in logging_outputs)
+        nsentences = sum(log.get("nsentences", 0) for log in logging_outputs)
+        sample_size = sum(log.get("sample_size", 0) for log in logging_outputs)
+        agg_output = {
+            "loss": loss_sum / nsentences,
+            "ntokens": ntokens,
+            "nsentences": nsentences,
+            "sample_size": sample_size,
+        }
+        return agg_output

examples/speech_recognition/criterions/__init__.py

@@ -0,0 +1,17 @@
+import importlib
+import os
+
+
+# ASG loss requires wav2letter
+files_to_skip = set()
+try:
+    import wav2letter
+except ImportError:
+    files_to_skip.add("ASG_loss.py")
+
+for file in os.listdir(os.path.dirname(__file__)):
+    if file.endswith(".py") and not file.startswith("_") and file not in files_to_skip:
+        criterion_name = file[: file.find(".py")]
+        importlib.import_module(
+            "examples.speech_recognition.criterions." + criterion_name
+        )

examples/speech_recognition/criterions/cross_entropy_acc.py

@@ -0,0 +1,130 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import logging
+import math
+
+import torch
+import torch.nn.functional as F
+from fairseq import utils
+from fairseq.criterions import FairseqCriterion, register_criterion
+
+
+@register_criterion("cross_entropy_acc")
+class CrossEntropyWithAccCriterion(FairseqCriterion):
+    def __init__(self, task, sentence_avg):
+        super().__init__(task)
+        self.sentence_avg = sentence_avg
+
+    def compute_loss(self, model, net_output, target, reduction, log_probs):
+        # N, T -> N * T
+        target = target.view(-1)
+        lprobs = model.get_normalized_probs(net_output, log_probs=log_probs)
+        if not hasattr(lprobs, "batch_first"):
+            logging.warning(
+                "ERROR: we need to know whether "
+                "batch first for the net output; "
+                "you need to set batch_first attribute for the return value of "
+                "model.get_normalized_probs. Now, we assume this is true, but "
+                "in the future, we will raise exception instead. "
+            )
+        batch_first = getattr(lprobs, "batch_first", True)
+        if not batch_first:
+            lprobs = lprobs.transpose(0, 1)
+
+        # N, T, D -> N * T, D
+        lprobs = lprobs.view(-1, lprobs.size(-1))
+        loss = F.nll_loss(
+            lprobs, target, ignore_index=self.padding_idx, reduction=reduction
+        )
+        return lprobs, loss
+
+    def get_logging_output(self, sample, target, lprobs, loss):
+        target = target.view(-1)
+        mask = target != self.padding_idx
+        correct = torch.sum(
+            lprobs.argmax(1).masked_select(mask) == target.masked_select(mask)
+        )
+        total = torch.sum(mask)
+        sample_size = (
+            sample["target"].size(0) if self.sentence_avg else sample["ntokens"]
+        )
+
+        logging_output = {
+            "loss": utils.item(loss.data),  # * sample['ntokens'],
+            "ntokens": sample["ntokens"],
+            "nsentences": sample["target"].size(0),
+            "sample_size": sample_size,
+            "correct": utils.item(correct.data),
+            "total": utils.item(total.data),
+            "nframes": torch.sum(sample["net_input"]["src_lengths"]).item(),
+        }
+
+        return sample_size, logging_output
+
+    def forward(self, model, sample, reduction="sum", log_probs=True):
+        """Computes the cross entropy with accuracy metric for the given sample.
+
+        This is similar to CrossEntropyCriterion in fairseq, but also
+        computes accuracy metrics as part of logging
+
+        Args:
+            logprobs (Torch.tensor) of shape N, T, D i.e.
+                batchsize, timesteps, dimensions
+            targets (Torch.tensor) of shape N, T  i.e batchsize, timesteps
+
+        Returns:
+        tuple: With three elements:
+            1) the loss
+            2) the sample size, which is used as the denominator for the gradient
+            3) logging outputs to display while training
+
+        TODO:
+            * Currently this Criterion will only work with LSTMEncoderModels or
+            FairseqModels which have decoder, or Models which return TorchTensor
+            as net_output.
+            We need to make a change to support all FairseqEncoder models.
+        """
+        net_output = model(**sample["net_input"])
+        target = model.get_targets(sample, net_output)
+        lprobs, loss = self.compute_loss(
+            model, net_output, target, reduction, log_probs
+        )
+        sample_size, logging_output = self.get_logging_output(
+            sample, target, lprobs, loss
+        )
+        return loss, sample_size, logging_output
+
+    @staticmethod
+    def aggregate_logging_outputs(logging_outputs):
+        """Aggregate logging outputs from data parallel training."""
+        correct_sum = sum(log.get("correct", 0) for log in logging_outputs)
+        total_sum = sum(log.get("total", 0) for log in logging_outputs)
+        loss_sum = sum(log.get("loss", 0) for log in logging_outputs)
+        ntokens = sum(log.get("ntokens", 0) for log in logging_outputs)
+        nsentences = sum(log.get("nsentences", 0) for log in logging_outputs)
+        sample_size = sum(log.get("sample_size", 0) for log in logging_outputs)
+        nframes = sum(log.get("nframes", 0) for log in logging_outputs)
+        agg_output = {
+            "loss": loss_sum / sample_size / math.log(2) if sample_size > 0 else 0.0,
+            # if args.sentence_avg, then sample_size is nsentences, then loss
+            # is per-sentence loss; else sample_size is ntokens, the loss
+            # becomes per-output token loss
+            "ntokens": ntokens,
+            "nsentences": nsentences,
+            "nframes": nframes,
+            "sample_size": sample_size,
+            "acc": correct_sum * 100.0 / total_sum if total_sum > 0 else 0.0,
+            "correct": correct_sum,
+            "total": total_sum,
+            # total is the number of validate tokens
+        }
+        if sample_size != ntokens:
+            agg_output["nll_loss"] = loss_sum / ntokens / math.log(2)
+        # loss: per output token loss
+        # nll_loss: per sentence loss
+        return agg_output

examples/speech_recognition/data/__init__.py

@@ -0,0 +1,11 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from .asr_dataset import AsrDataset
+
+
+__all__ = [
+    "AsrDataset",
+]

examples/speech_recognition/data/asr_dataset.py

@@ -0,0 +1,122 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import os
+
+import numpy as np
+from fairseq.data import FairseqDataset
+
+from . import data_utils
+from .collaters import Seq2SeqCollater
+
+
+class AsrDataset(FairseqDataset):
+    """
+    A dataset representing speech and corresponding transcription.
+
+    Args:
+        aud_paths: (List[str]): A list of str with paths to audio files.
+        aud_durations_ms (List[int]): A list of int containing the durations of
+            audio files.
+        tgt (List[torch.LongTensor]): A list of LongTensors containing the indices
+            of target transcriptions.
+        tgt_dict (~fairseq.data.Dictionary): target vocabulary.
+        ids (List[str]): A list of utterance IDs.
+        speakers (List[str]): A list of speakers corresponding to utterances.
+        num_mel_bins (int): Number of triangular mel-frequency bins (default: 80)
+        frame_length (float): Frame length in milliseconds (default: 25.0)
+        frame_shift (float): Frame shift in milliseconds (default: 10.0)
+    """
+
+    def __init__(
+        self,
+        aud_paths,
+        aud_durations_ms,
+        tgt,
+        tgt_dict,
+        ids,
+        speakers,
+        num_mel_bins=80,
+        frame_length=25.0,
+        frame_shift=10.0,
+    ):
+        assert frame_length > 0
+        assert frame_shift > 0
+        assert all(x > frame_length for x in aud_durations_ms)
+        self.frame_sizes = [
+            int(1 + (d - frame_length) / frame_shift) for d in aud_durations_ms
+        ]
+
+        assert len(aud_paths) > 0
+        assert len(aud_paths) == len(aud_durations_ms)
+        assert len(aud_paths) == len(tgt)
+        assert len(aud_paths) == len(ids)
+        assert len(aud_paths) == len(speakers)
+        self.aud_paths = aud_paths
+        self.tgt_dict = tgt_dict
+        self.tgt = tgt
+        self.ids = ids
+        self.speakers = speakers
+        self.num_mel_bins = num_mel_bins
+        self.frame_length = frame_length
+        self.frame_shift = frame_shift
+
+        self.s2s_collater = Seq2SeqCollater(
+            0,
+            1,
+            pad_index=self.tgt_dict.pad(),
+            eos_index=self.tgt_dict.eos(),
+            move_eos_to_beginning=True,
+        )
+
+    def __getitem__(self, index):
+        import torchaudio
+        import torchaudio.compliance.kaldi as kaldi
+
+        tgt_item = self.tgt[index] if self.tgt is not None else None
+
+        path = self.aud_paths[index]
+        if not os.path.exists(path):
+            raise FileNotFoundError("Audio file not found: {}".format(path))
+        sound, sample_rate = torchaudio.load_wav(path)
+        output = kaldi.fbank(
+            sound,
+            num_mel_bins=self.num_mel_bins,
+            frame_length=self.frame_length,
+            frame_shift=self.frame_shift,
+        )
+        output_cmvn = data_utils.apply_mv_norm(output)
+
+        return {"id": index, "data": [output_cmvn.detach(), tgt_item]}
+
+    def __len__(self):
+        return len(self.aud_paths)
+
+    def collater(self, samples):
+        """Merge a list of samples to form a mini-batch.
+
+        Args:
+            samples (List[int]): sample indices to collate
+
+        Returns:
+            dict: a mini-batch suitable for forwarding with a Model
+        """
+        return self.s2s_collater.collate(samples)
+
+    def num_tokens(self, index):
+        return self.frame_sizes[index]
+
+    def size(self, index):
+        """Return an example's size as a float or tuple. This value is used when
+        filtering a dataset with ``--max-positions``."""
+        return (
+            self.frame_sizes[index],
+            len(self.tgt[index]) if self.tgt is not None else 0,
+        )
+
+    def ordered_indices(self):
+        """Return an ordered list of indices. Batches will be constructed based
+        on this order."""
+        return np.arange(len(self))

examples/speech_recognition/data/collaters.py

@@ -0,0 +1,131 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+"""
+    This module contains collection of classes which implement
+    collate functionalities for various tasks.
+
+    Collaters should know what data to expect for each sample
+    and they should pack / collate them into batches
+"""
+
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import numpy as np
+import torch
+from fairseq.data import data_utils as fairseq_data_utils
+
+
+class Seq2SeqCollater(object):
+    """
+    Implements collate function mainly for seq2seq tasks
+    This expects each sample to contain feature (src_tokens) and
+    targets.
+    This collator is also used for aligned training task.
+    """
+
+    def __init__(
+        self,
+        feature_index=0,
+        label_index=1,
+        pad_index=1,
+        eos_index=2,
+        move_eos_to_beginning=True,
+    ):
+        self.feature_index = feature_index
+        self.label_index = label_index
+        self.pad_index = pad_index
+        self.eos_index = eos_index
+        self.move_eos_to_beginning = move_eos_to_beginning
+
+    def _collate_frames(self, frames):
+        """Convert a list of 2d frames into a padded 3d tensor
+        Args:
+            frames (list): list of 2d frames of size L[i]*f_dim. Where L[i] is
+                length of i-th frame and f_dim is static dimension of features
+        Returns:
+            3d tensor of size len(frames)*len_max*f_dim where len_max is max of L[i]
+        """
+        len_max = max(frame.size(0) for frame in frames)
+        f_dim = frames[0].size(1)
+        res = frames[0].new(len(frames), len_max, f_dim).fill_(0.0)
+
+        for i, v in enumerate(frames):
+            res[i, : v.size(0)] = v
+
+        return res
+
+    def collate(self, samples):
+        """
+        utility function to collate samples into batch for speech recognition.
+        """
+        if len(samples) == 0:
+            return {}
+
+        # parse samples into torch tensors
+        parsed_samples = []
+        for s in samples:
+            # skip invalid samples
+            if s["data"][self.feature_index] is None:
+                continue
+            source = s["data"][self.feature_index]
+            if isinstance(source, (np.ndarray, np.generic)):
+                source = torch.from_numpy(source)
+            target = s["data"][self.label_index]
+            if isinstance(target, (np.ndarray, np.generic)):
+                target = torch.from_numpy(target).long()
+            elif isinstance(target, list):
+                target = torch.LongTensor(target)
+
+            parsed_sample = {"id": s["id"], "source": source, "target": target}
+            parsed_samples.append(parsed_sample)
+        samples = parsed_samples
+
+        id = torch.LongTensor([s["id"] for s in samples])
+        frames = self._collate_frames([s["source"] for s in samples])
+        # sort samples by descending number of frames
+        frames_lengths = torch.LongTensor([s["source"].size(0) for s in samples])
+        frames_lengths, sort_order = frames_lengths.sort(descending=True)
+        id = id.index_select(0, sort_order)
+        frames = frames.index_select(0, sort_order)
+
+        target = None
+        target_lengths = None
+        prev_output_tokens = None
+        if samples[0].get("target", None) is not None:
+            ntokens = sum(len(s["target"]) for s in samples)
+            target = fairseq_data_utils.collate_tokens(
+                [s["target"] for s in samples],
+                self.pad_index,
+                self.eos_index,
+                left_pad=False,
+                move_eos_to_beginning=False,
+            )
+            target = target.index_select(0, sort_order)
+            target_lengths = torch.LongTensor(
+                [s["target"].size(0) for s in samples]
+            ).index_select(0, sort_order)
+            prev_output_tokens = fairseq_data_utils.collate_tokens(
+                [s["target"] for s in samples],
+                self.pad_index,
+                self.eos_index,
+                left_pad=False,
+                move_eos_to_beginning=self.move_eos_to_beginning,
+            )
+            prev_output_tokens = prev_output_tokens.index_select(0, sort_order)
+        else:
+            ntokens = sum(len(s["source"]) for s in samples)
+
+        batch = {
+            "id": id,
+            "ntokens": ntokens,
+            "net_input": {"src_tokens": frames, "src_lengths": frames_lengths},
+            "target": target,
+            "target_lengths": target_lengths,
+            "nsentences": len(samples),
+        }
+        if prev_output_tokens is not None:
+            batch["net_input"]["prev_output_tokens"] = prev_output_tokens
+        return batch

examples/speech_recognition/data/data_utils.py

@@ -0,0 +1,100 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import torch
+
+
+def calc_mean_invstddev(feature):
+    if len(feature.size()) != 2:
+        raise ValueError("We expect the input feature to be 2-D tensor")
+    mean = feature.mean(0)
+    var = feature.var(0)
+    # avoid division by ~zero
+    eps = 1e-8
+    if (var < eps).any():
+        return mean, 1.0 / (torch.sqrt(var) + eps)
+    return mean, 1.0 / torch.sqrt(var)
+
+
+def apply_mv_norm(features):
+    # If there is less than 2 spectrograms, the variance cannot be computed (is NaN)
+    # and normalization is not possible, so return the item as it is
+    if features.size(0) < 2:
+        return features
+    mean, invstddev = calc_mean_invstddev(features)
+    res = (features - mean) * invstddev
+    return res
+
+
+def lengths_to_encoder_padding_mask(lengths, batch_first=False):
+    """
+    convert lengths (a 1-D Long/Int tensor) to 2-D binary tensor
+
+    Args:
+        lengths: a (B, )-shaped tensor
+
+    Return:
+        max_length: maximum length of B sequences
+        encoder_padding_mask: a (max_length, B) binary mask, where
+        [t, b] = 0 for t < lengths[b] and 1 otherwise
+
+    TODO:
+        kernelize this function if benchmarking shows this function is slow
+    """
+    max_lengths = torch.max(lengths).item()
+    bsz = lengths.size(0)
+    encoder_padding_mask = torch.arange(
+        max_lengths
+    ).to(  # a (T, ) tensor with [0, ..., T-1]
+        lengths.device
+    ).view(  # move to the right device
+        1, max_lengths
+    ).expand(  # reshape to (1, T)-shaped tensor
+        bsz, -1
+    ) >= lengths.view(  # expand to (B, T)-shaped tensor
+        bsz, 1
+    ).expand(
+        -1, max_lengths
+    )
+    if not batch_first:
+        return encoder_padding_mask.t(), max_lengths
+    else:
+        return encoder_padding_mask, max_lengths
+
+
+def encoder_padding_mask_to_lengths(
+    encoder_padding_mask, max_lengths, batch_size, device
+):
+    """
+    convert encoder_padding_mask (2-D binary tensor) to a 1-D tensor
+
+    Conventionally, encoder output contains a encoder_padding_mask, which is
+    a 2-D mask in a shape (T, B), whose (t, b) element indicate whether
+    encoder_out[t, b] is a valid output (=0) or not (=1). Occasionally, we
+    need to convert this mask tensor to a 1-D tensor in shape (B, ), where
+    [b] denotes the valid length of b-th sequence
+
+    Args:
+        encoder_padding_mask: a (T, B)-shaped binary tensor or None; if None,
+        indicating all are valid
+    Return:
+        seq_lengths: a (B,)-shaped tensor, where its (b, )-th element is the
+        number of valid elements of b-th sequence
+
+        max_lengths: maximum length of all sequence, if encoder_padding_mask is
+        not None, max_lengths must equal to encoder_padding_mask.size(0)
+
+        batch_size: batch size; if encoder_padding_mask is
+        not None, max_lengths must equal to encoder_padding_mask.size(1)
+
+        device: which device to put the result on
+    """
+    if encoder_padding_mask is None:
+        return torch.Tensor([max_lengths] * batch_size).to(torch.int32).to(device)
+
+    assert encoder_padding_mask.size(0) == max_lengths, "max_lengths does not match"
+    assert encoder_padding_mask.size(1) == batch_size, "batch_size does not match"
+
+    return max_lengths - torch.sum(encoder_padding_mask, dim=0)

examples/speech_recognition/data/replabels.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""
+Replabel transforms for use with wav2letter's ASG criterion.
+"""
+
+
+def replabel_symbol(i):
+    """
+    Replabel symbols used in wav2letter, currently just "1", "2", ...
+    This prevents training with numeral tokens, so this might change in the future
+    """
+    return str(i)
+
+
+def pack_replabels(tokens, dictionary, max_reps):
+    """
+    Pack a token sequence so that repeated symbols are replaced by replabels
+    """
+    if len(tokens) == 0 or max_reps <= 0:
+        return tokens
+
+    replabel_value_to_idx = [0] * (max_reps + 1)
+    for i in range(1, max_reps + 1):
+        replabel_value_to_idx[i] = dictionary.index(replabel_symbol(i))
+
+    result = []
+    prev_token = -1
+    num_reps = 0
+    for token in tokens:
+        if token == prev_token and num_reps < max_reps:
+            num_reps += 1
+        else:
+            if num_reps > 0:
+                result.append(replabel_value_to_idx[num_reps])
+                num_reps = 0
+            result.append(token)
+            prev_token = token
+    if num_reps > 0:
+        result.append(replabel_value_to_idx[num_reps])
+    return result
+
+
+def unpack_replabels(tokens, dictionary, max_reps):
+    """
+    Unpack a token sequence so that replabels are replaced by repeated symbols
+    """
+    if len(tokens) == 0 or max_reps <= 0:
+        return tokens
+
+    replabel_idx_to_value = {}
+    for i in range(1, max_reps + 1):
+        replabel_idx_to_value[dictionary.index(replabel_symbol(i))] = i
+
+    result = []
+    prev_token = -1
+    for token in tokens:
+        try:
+            for _ in range(replabel_idx_to_value[token]):
+                result.append(prev_token)
+            prev_token = -1
+        except KeyError:
+            result.append(token)
+            prev_token = token
+    return result

examples/speech_recognition/datasets/asr_prep_json.py

@@ -0,0 +1,125 @@
+#!/usr/bin/env python3
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import argparse
+import concurrent.futures
+import json
+import multiprocessing
+import os
+from collections import namedtuple
+from itertools import chain
+
+import sentencepiece as spm
+from fairseq.data import Dictionary
+
+
+MILLISECONDS_TO_SECONDS = 0.001
+
+
+def process_sample(aud_path, lable, utt_id, sp, tgt_dict):
+    import torchaudio
+
+    input = {}
+    output = {}
+    si, ei = torchaudio.info(aud_path)
+    input["length_ms"] = int(
+        si.length / si.channels / si.rate / MILLISECONDS_TO_SECONDS
+    )
+    input["path"] = aud_path
+
+    token = " ".join(sp.EncodeAsPieces(lable))
+    ids = tgt_dict.encode_line(token, append_eos=False)
+    output["text"] = lable
+    output["token"] = token
+    output["tokenid"] = ", ".join(map(str, [t.tolist() for t in ids]))
+    return {utt_id: {"input": input, "output": output}}
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--audio-dirs",
+        nargs="+",
+        default=["-"],
+        required=True,
+        help="input directories with audio files",
+    )
+    parser.add_argument(
+        "--labels",
+        required=True,
+        help="aggregated input labels with format <ID LABEL> per line",
+        type=argparse.FileType("r", encoding="UTF-8"),
+    )
+    parser.add_argument(
+        "--spm-model",
+        required=True,
+        help="sentencepiece model to use for encoding",
+        type=argparse.FileType("r", encoding="UTF-8"),
+    )
+    parser.add_argument(
+        "--dictionary",
+        required=True,
+        help="file to load fairseq dictionary from",
+        type=argparse.FileType("r", encoding="UTF-8"),
+    )
+    parser.add_argument("--audio-format", choices=["flac", "wav"], default="wav")
+    parser.add_argument(
+        "--output",
+        required=True,
+        type=argparse.FileType("w"),
+        help="path to save json output",
+    )
+    args = parser.parse_args()
+
+    sp = spm.SentencePieceProcessor()
+    sp.Load(args.spm_model.name)
+
+    tgt_dict = Dictionary.load(args.dictionary)
+
+    labels = {}
+    for line in args.labels:
+        (utt_id, label) = line.split(" ", 1)
+        labels[utt_id] = label
+    if len(labels) == 0:
+        raise Exception("No labels found in ", args.labels_path)
+
+    Sample = namedtuple("Sample", "aud_path utt_id")
+    samples = []
+    for path, _, files in chain.from_iterable(
+        os.walk(path) for path in args.audio_dirs
+    ):
+        for f in files:
+            if f.endswith(args.audio_format):
+                if len(os.path.splitext(f)) != 2:
+                    raise Exception("Expect <utt_id.extension> file name. Got: ", f)
+                utt_id = os.path.splitext(f)[0]
+                if utt_id not in labels:
+                    continue
+                samples.append(Sample(os.path.join(path, f), utt_id))
+
+    utts = {}
+    num_cpu = multiprocessing.cpu_count()
+    with concurrent.futures.ThreadPoolExecutor(max_workers=num_cpu) as executor:
+        future_to_sample = {
+            executor.submit(
+                process_sample, s.aud_path, labels[s.utt_id], s.utt_id, sp, tgt_dict
+            ): s
+            for s in samples
+        }
+        for future in concurrent.futures.as_completed(future_to_sample):
+            try:
+                data = future.result()
+            except Exception as exc:
+                print("generated an exception: ", exc)
+            else:
+                utts.update(data)
+    json.dump({"utts": utts}, args.output, indent=4)
+
+
+if __name__ == "__main__":
+    main()

examples/speech_recognition/datasets/prepare-librispeech.sh

@@ -0,0 +1,88 @@
+#!/usr/bin/env bash
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+# Prepare librispeech dataset
+
+base_url=www.openslr.org/resources/12
+train_dir=train_960
+
+if [ "$#" -ne 2 ]; then
+  echo "Usage: $0 <download_dir> <out_dir>"
+  echo "e.g.: $0 /tmp/librispeech_raw/ ~/data/librispeech_final"
+  exit 1
+fi
+
+download_dir=${1%/}
+out_dir=${2%/}
+
+fairseq_root=~/fairseq-py/
+mkdir -p ${out_dir}
+cd ${out_dir} || exit
+
+nbpe=5000
+bpemode=unigram
+
+if [ ! -d "$fairseq_root" ]; then
+    echo "$0: Please set correct fairseq_root"
+    exit 1
+fi
+
+echo "Data Download"
+for part in dev-clean test-clean dev-other test-other train-clean-100 train-clean-360 train-other-500; do
+    url=$base_url/$part.tar.gz
+    if ! wget -P $download_dir $url; then
+        echo "$0: wget failed for $url"
+        exit 1
+    fi
+    if ! tar -C $download_dir -xvzf $download_dir/$part.tar.gz; then
+        echo "$0: error un-tarring archive $download_dir/$part.tar.gz"
+        exit 1
+    fi
+done
+
+echo "Merge all train packs into one"
+mkdir -p ${download_dir}/LibriSpeech/${train_dir}/
+for part in train-clean-100 train-clean-360 train-other-500; do
+    mv ${download_dir}/LibriSpeech/${part}/* $download_dir/LibriSpeech/${train_dir}/
+done
+echo "Merge train text"
+find ${download_dir}/LibriSpeech/${train_dir}/ -name '*.txt' -exec cat {} \; >> ${download_dir}/LibriSpeech/${train_dir}/text
+
+# Use combined dev-clean and dev-other as validation set
+find ${download_dir}/LibriSpeech/dev-clean/ ${download_dir}/LibriSpeech/dev-other/ -name '*.txt' -exec cat {} \; >> ${download_dir}/LibriSpeech/valid_text
+find ${download_dir}/LibriSpeech/test-clean/ -name '*.txt' -exec cat {} \; >> ${download_dir}/LibriSpeech/test-clean/text
+find ${download_dir}/LibriSpeech/test-other/ -name '*.txt' -exec cat {} \; >> ${download_dir}/LibriSpeech/test-other/text
+
+
+dict=data/lang_char/${train_dir}_${bpemode}${nbpe}_units.txt
+encoded=data/lang_char/${train_dir}_${bpemode}${nbpe}_encoded.txt
+fairseq_dict=data/lang_char/${train_dir}_${bpemode}${nbpe}_fairseq_dict.txt
+bpemodel=data/lang_char/${train_dir}_${bpemode}${nbpe}
+echo "dictionary: ${dict}"
+echo "Dictionary preparation"
+mkdir -p data/lang_char/
+echo "<unk> 3" > ${dict}
+echo "</s> 2" >> ${dict}
+echo "<pad> 1" >> ${dict}
+cut -f 2- -d" " ${download_dir}/LibriSpeech/${train_dir}/text > data/lang_char/input.txt
+spm_train --input=data/lang_char/input.txt --vocab_size=${nbpe} --model_type=${bpemode} --model_prefix=${bpemodel} --input_sentence_size=100000000 --unk_id=3 --eos_id=2 --pad_id=1 --bos_id=-1 --character_coverage=1
+spm_encode --model=${bpemodel}.model --output_format=piece < data/lang_char/input.txt > ${encoded}
+cat ${encoded} | tr ' ' '\n' | sort | uniq | awk '{print $0 " " NR+3}' >> ${dict}
+cat ${encoded} | tr ' ' '\n' | sort | uniq -c | awk '{print $2 " " $1}' > ${fairseq_dict}
+wc -l ${dict}
+
+echo "Prepare train and test jsons"
+for part in train_960 test-other test-clean; do
+    python ${fairseq_root}/examples/speech_recognition/datasets/asr_prep_json.py --audio-dirs ${download_dir}/LibriSpeech/${part} --labels ${download_dir}/LibriSpeech/${part}/text --spm-model ${bpemodel}.model --audio-format flac --dictionary ${fairseq_dict} --output ${part}.json
+done
+# fairseq expects to find train.json and valid.json during training
+mv train_960.json train.json
+
+echo "Prepare valid json"
+python ${fairseq_root}/examples/speech_recognition/datasets/asr_prep_json.py --audio-dirs ${download_dir}/LibriSpeech/dev-clean ${download_dir}/LibriSpeech/dev-other --labels ${download_dir}/LibriSpeech/valid_text --spm-model ${bpemodel}.model --audio-format flac --dictionary ${fairseq_dict} --output valid.json
+
+cp ${fairseq_dict} ./dict.txt
+cp ${bpemodel}.model ./spm.model

examples/speech_recognition/infer.py

@@ -0,0 +1,474 @@
+#!/usr/bin/env python3 -u
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""
+Run inference for pre-processed data with a trained model.
+"""
+
+import logging
+import math
+import os
+import sys
+if '/home/fairseq' in sys.path:
+    sys.path.remove('/home/fairseq')
+sys.path.append('/datablob/users/v-chengw/pyproj/fairseq')
+
+import editdistance
+import numpy as np
+import torch
+from fairseq import checkpoint_utils, options, progress_bar, tasks, utils, pdb
+from fairseq.data.data_utils import post_process
+from fairseq.dataclass.utils import convert_namespace_to_omegaconf
+from fairseq.logging.meters import StopwatchMeter, TimeMeter
+
+
+logging.basicConfig()
+logging.root.setLevel(logging.INFO)
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+
+def add_asr_eval_argument(parser):
+    parser.add_argument("--kspmodel", default=None, help="sentence piece model")
+    parser.add_argument(
+        "--wfstlm", default=None, help="wfstlm on dictonary output units"
+    )
+    parser.add_argument(
+        "--rnnt_decoding_type",
+        default="greedy",
+        help="wfstlm on dictonary\
+output units",
+    )
+    try:
+        parser.add_argument(
+            "--lm-weight",
+            "--lm_weight",
+            type=float,
+            default=0.2,
+            help="weight for lm while interpolating with neural score",
+        )
+    except:
+        pass
+    parser.add_argument(
+        "--rnnt_len_penalty", default=-0.5, help="rnnt length penalty on word level"
+    )
+    parser.add_argument(
+        "--w2l-decoder",
+        choices=["viterbi", "kenlm", "fairseqlm"],
+        help="use a w2l decoder",
+    )
+    parser.add_argument("--lexicon", help="lexicon for w2l decoder")
+    parser.add_argument("--unit-lm", action="store_true", help="if using a unit lm")
+    parser.add_argument("--kenlm-model", "--lm-model", help="lm model for w2l decoder")
+    parser.add_argument("--beam-threshold", type=float, default=25.0)
+    parser.add_argument("--beam-size-token", type=float, default=100)
+    parser.add_argument("--word-score", type=float, default=1.0)
+    parser.add_argument("--unk-weight", type=float, default=-math.inf)
+    parser.add_argument("--sil-weight", type=float, default=0.0)
+    parser.add_argument(
+        "--dump-emissions",
+        type=str,
+        default=None,
+        help="if present, dumps emissions into this file and exits",
+    )
+    parser.add_argument(
+        "--dump-features",
+        type=str,
+        default=None,
+        help="if present, dumps features into this file and exits",
+    )
+    parser.add_argument(
+        "--load-emissions",
+        type=str,
+        default=None,
+        help="if present, loads emissions from this file",
+    )
+    return parser
+
+
+def check_args(args):
+    # assert args.path is not None, "--path required for generation!"
+    # assert args.results_path is not None, "--results_path required for generation!"
+    assert (
+        not args.sampling or args.nbest == args.beam
+    ), "--sampling requires --nbest to be equal to --beam"
+    assert (
+        args.replace_unk is None or args.raw_text
+    ), "--replace-unk requires a raw text dataset (--raw-text)"
+
+
+def get_dataset_itr(args, task, models):
+    return task.get_batch_iterator(
+        dataset=task.dataset(args.gen_subset),
+        max_tokens=args.max_tokens,
+        max_sentences=args.batch_size,
+        max_positions=(sys.maxsize, sys.maxsize),
+        ignore_invalid_inputs=args.skip_invalid_size_inputs_valid_test,
+        required_batch_size_multiple=args.required_batch_size_multiple,
+        num_shards=args.num_shards,
+        shard_id=args.shard_id,
+        num_workers=args.num_workers,
+        data_buffer_size=args.data_buffer_size,
+    ).next_epoch_itr(shuffle=False)
+
+
+def process_predictions(
+    args, hypos, sp, tgt_dict, target_tokens, res_files, speaker, id
+):
+    for hypo in hypos[: min(len(hypos), args.nbest)]:
+        hyp_pieces = tgt_dict.string(hypo["tokens"].int().cpu())
+
+        if "words" in hypo:
+            hyp_words = " ".join(hypo["words"])
+        else:
+            hyp_words = post_process(hyp_pieces, args.post_process)
+
+        if res_files is not None:
+            print(
+                "{} ({}-{})".format(hyp_pieces, speaker, id),
+                file=res_files["hypo.units"],
+            )
+            print(
+                "{} ({}-{})".format(hyp_words, speaker, id),
+                file=res_files["hypo.words"],
+            )
+
+        tgt_pieces = tgt_dict.string(target_tokens)
+        tgt_words = post_process(tgt_pieces, args.post_process)
+
+        if res_files is not None:
+            print(
+                "{} ({}-{})".format(tgt_pieces, speaker, id),
+                file=res_files["ref.units"],
+            )
+            print(
+                "{} ({}-{})".format(tgt_words, speaker, id), file=res_files["ref.words"]
+            )
+            # only score top hypothesis
+            if not args.quiet:
+                logger.debug("HYPO:" + hyp_words)
+                logger.debug("TARGET:" + tgt_words)
+                logger.debug("___________________")
+
+        hyp_words = hyp_words.split()
+        tgt_words = tgt_words.split()
+        return editdistance.eval(hyp_words, tgt_words), len(tgt_words)
+
+
+def prepare_result_files(args):
+    def get_res_file(file_prefix):
+        if args.num_shards > 1:
+            file_prefix = f"{args.shard_id}_{file_prefix}"
+        path = os.path.join(
+            args.results_path,
+            "{}-{}-{}.txt".format(
+                file_prefix, os.path.basename(args.path), args.gen_subset
+            ),
+        )
+        return open(path, "w", buffering=1)
+
+    if not args.results_path:
+        return None
+
+    return {
+        "hypo.words": get_res_file("hypo.word"),
+        "hypo.units": get_res_file("hypo.units"),
+        "ref.words": get_res_file("ref.word"),
+        "ref.units": get_res_file("ref.units"),
+    }
+
+
+def load_models_and_criterions(
+    filenames, data_path, arg_overrides=None, task=None, model_state=None
+):
+    models = []
+    criterions = []
+
+    if arg_overrides is None:
+        arg_overrides = {}
+
+    arg_overrides["wer_args"] = None
+    arg_overrides["data"] = data_path
+
+    if filenames is None:
+        assert model_state is not None
+        filenames = [0]
+    else:
+        filenames = filenames.split(":")
+
+    for filename in filenames:
+        if model_state is None:
+            if not os.path.exists(filename):
+                raise IOError("Model file not found: {}".format(filename))
+            state = checkpoint_utils.load_checkpoint_to_cpu(filename, arg_overrides)
+        else:
+            state = model_state
+
+        if "cfg" in state:
+            cfg = state["cfg"]
+        else:
+            cfg = convert_namespace_to_omegaconf(state["args"])
+
+        if task is None:
+            if hasattr(cfg.task, 'data'):
+                cfg.task.data = data_path
+            task = tasks.setup_task(cfg.task)
+
+        model = task.build_model(cfg.model)
+        model.load_state_dict(state["model"], strict=True)
+        models.append(model)
+
+        criterion = task.build_criterion(cfg.criterion)
+        if "criterion" in state:
+            criterion.load_state_dict(state["criterion"], strict=True)
+        criterions.append(criterion)
+    return models, criterions, task
+
+
+def optimize_models(args, use_cuda, models):
+    """Optimize ensemble for generation"""
+    for model in models:
+        model.make_generation_fast_(
+            beamable_mm_beam_size=None if args.no_beamable_mm else args.beam,
+            need_attn=args.print_alignment,
+        )
+        if args.fp16:
+            model.half()
+        if use_cuda:
+            model.cuda()
+
+
+class ExistingEmissionsDecoder(object):
+    def __init__(self, decoder, emissions):
+        self.decoder = decoder
+        self.emissions = emissions
+
+    def generate(self, models, sample, **unused):
+        ids = sample["id"].cpu().numpy()
+        try:
+            emissions = np.stack(self.emissions[ids])
+        except:
+            print([x.shape for x in self.emissions[ids]])
+            raise Exception("invalid sizes")
+        emissions = torch.from_numpy(emissions)
+        return self.decoder.decode(emissions)
+
+
+def main(args, task=None, model_state=None):
+    check_args(args)
+
+    if args.max_tokens is None and args.batch_size is None:
+        args.max_tokens = 4000000
+    logger.info(args)
+
+    use_cuda = torch.cuda.is_available() and not args.cpu
+
+
+    logger.info("| decoding with criterion {}".format(args.criterion))
+
+    # Load ensemble
+    if args.load_emissions:
+        models, criterions = [], []
+        task = tasks.setup_task(args)
+    else:
+        logger.info("| loading model(s) from {}".format(args.path))
+        models, criterions, task = load_models_and_criterions(
+            args.path,
+            data_path=args.data,
+            arg_overrides=eval(args.model_overrides),  # noqa
+            task=task,
+            model_state=model_state,
+        )
+        optimize_models(args, use_cuda, models)
+
+    # Load dataset splits
+    task.load_dataset(args.gen_subset)
+
+    # Set dictionary
+    tgt_dict = task.target_dictionary
+
+    logger.info(
+        "| {} {} {} examples".format(
+            args.data, args.gen_subset, len(task.dataset(args.gen_subset))
+        )
+    )
+
+    # hack to pass transitions to W2lDecoder
+    if args.criterion == "asg_loss":
+        trans = criterions[0].asg.trans.data
+        args.asg_transitions = torch.flatten(trans).tolist()
+
+    # Load dataset (possibly sharded)
+    itr = get_dataset_itr(args, task, models)
+
+    # Initialize generator
+    gen_timer = StopwatchMeter()
+
+    def build_generator(args):
+        w2l_decoder = getattr(args, "w2l_decoder", None)
+        if w2l_decoder == "viterbi":
+            from examples.speech_recognition.w2l_decoder import W2lViterbiDecoder
+
+            return W2lViterbiDecoder(args, task.target_dictionary)
+        elif w2l_decoder == "kenlm":
+            from examples.speech_recognition.w2l_decoder import W2lKenLMDecoder
+
+            return W2lKenLMDecoder(args, task.target_dictionary)
+        elif w2l_decoder == "fairseqlm":
+            from examples.speech_recognition.w2l_decoder import W2lFairseqLMDecoder
+
+            return W2lFairseqLMDecoder(args, task.target_dictionary)
+        else:
+            print(
+                "only wav2letter decoders with (viterbi, kenlm, fairseqlm) options are supported at the moment"
+            )
+
+    # please do not touch this unless you test both generate.py and infer.py with audio_pretraining task
+    generator = build_generator(args)
+
+    if args.load_emissions:
+        generator = ExistingEmissionsDecoder(
+            generator, np.load(args.load_emissions, allow_pickle=True)
+        )
+        logger.info("loaded emissions from " + args.load_emissions)
+
+    num_sentences = 0
+
+    if args.results_path is not None and not os.path.exists(args.results_path):
+        os.makedirs(args.results_path)
+
+    max_source_pos = (
+        utils.resolve_max_positions(
+            task.max_positions(), *[model.max_positions() for model in models]
+        ),
+    )
+
+    if max_source_pos is not None:
+        max_source_pos = max_source_pos[0]
+        if max_source_pos is not None:
+            max_source_pos = max_source_pos[0] - 1
+
+    if args.dump_emissions:
+        emissions = {}
+    if args.dump_features:
+        features = {}
+        models[0].bert.proj = None
+    else:
+        res_files = prepare_result_files(args)
+    errs_t = 0
+    lengths_t = 0
+    with progress_bar.build_progress_bar(args, itr) as t:
+        wps_meter = TimeMeter()
+        for sample in t:
+            sample = utils.move_to_cuda(sample) if use_cuda else sample
+            if "net_input" not in sample:
+                continue
+
+            prefix_tokens = None
+            if args.prefix_size > 0:
+                prefix_tokens = sample["target"][:, : args.prefix_size]
+
+            gen_timer.start()
+            if args.dump_emissions:
+                with torch.no_grad():
+                    encoder_out = models[0](**sample["net_input"])
+                    emm = models[0].get_normalized_probs(encoder_out, log_probs=True)
+                    emm = emm.transpose(0, 1).cpu().numpy()
+                    for i, id in enumerate(sample["id"]):
+                        emissions[id.item()] = emm[i]
+                    continue
+            elif args.dump_features:
+                with torch.no_grad():
+                    encoder_out = models[0](**sample["net_input"])
+                    feat = encoder_out["encoder_out"].transpose(0, 1).cpu().numpy()
+                    for i, id in enumerate(sample["id"]):
+                        padding = (
+                            encoder_out["encoder_padding_mask"][i].cpu().numpy()
+                            if encoder_out["encoder_padding_mask"] is not None
+                            else None
+                        )
+                        features[id.item()] = (feat[i], padding)
+                    continue
+            hypos = task.inference_step(generator, models, sample, prefix_tokens)
+            num_generated_tokens = sum(len(h[0]["tokens"]) for h in hypos)
+            gen_timer.stop(num_generated_tokens)
+
+            for i, sample_id in enumerate(sample["id"].tolist()):
+                speaker = None
+                # id = task.dataset(args.gen_subset).ids[int(sample_id)]
+                id = sample_id
+                toks = (
+                    sample["target"][i, :]
+                    if "target_label" not in sample
+                    else sample["target_label"][i, :]
+                )
+                target_tokens = utils.strip_pad(toks, tgt_dict.pad()).int().cpu()
+                # Process top predictions
+                errs, length = process_predictions(
+                    args,
+                    hypos[i],
+                    None,
+                    tgt_dict,
+                    target_tokens,
+                    res_files,
+                    speaker,
+                    id,
+                )
+                errs_t += errs
+                lengths_t += length
+
+            wps_meter.update(num_generated_tokens)
+            t.log({"wps": round(wps_meter.avg)})
+            num_sentences += (
+                sample["nsentences"] if "nsentences" in sample else sample["id"].numel()
+            )
+
+    wer = None
+    if args.dump_emissions:
+        emm_arr = []
+        for i in range(len(emissions)):
+            emm_arr.append(emissions[i])
+        np.save(args.dump_emissions, emm_arr)
+        logger.info(f"saved {len(emissions)} emissions to {args.dump_emissions}")
+    elif args.dump_features:
+        feat_arr = []
+        for i in range(len(features)):
+            feat_arr.append(features[i])
+        np.save(args.dump_features, feat_arr)
+        logger.info(f"saved {len(features)} emissions to {args.dump_features}")
+    else:
+        if lengths_t > 0:
+            wer = errs_t * 100.0 / lengths_t
+            logger.info(f"WER: {wer}")
+
+        logger.info(
+            "| Processed {} sentences ({} tokens) in {:.1f}s ({:.2f}"
+            "sentences/s, {:.2f} tokens/s)".format(
+                num_sentences,
+                gen_timer.n,
+                gen_timer.sum,
+                num_sentences / gen_timer.sum,
+                1.0 / gen_timer.avg,
+            )
+        )
+        logger.info("| Generate {} with beam={}".format(args.gen_subset, args.beam))
+    return task, wer
+
+
+def make_parser():
+    parser = options.get_generation_parser()
+    parser = add_asr_eval_argument(parser)
+    return parser
+
+
+def cli_main():
+    parser = make_parser()
+    args = options.parse_args_and_arch(parser)
+    main(args)
+
+
+if __name__ == "__main__":
+    cli_main()

examples/speech_recognition/models/__init__.py

@@ -0,0 +1,8 @@
+import importlib
+import os
+
+
+for file in os.listdir(os.path.dirname(__file__)):
+    if file.endswith(".py") and not file.startswith("_"):
+        model_name = file[: file.find(".py")]
+        importlib.import_module("examples.speech_recognition.models." + model_name)

examples/speech_recognition/models/w2l_conv_glu_enc.py

@@ -0,0 +1,177 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import math
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from fairseq.models import (
+    FairseqEncoder,
+    FairseqEncoderModel,
+    register_model,
+    register_model_architecture,
+)
+from fairseq.modules.fairseq_dropout import FairseqDropout
+
+
+default_conv_enc_config = """[
+    (400, 13, 170, 0.2),
+    (440, 14, 0, 0.214),
+    (484, 15, 0, 0.22898),
+    (532, 16, 0, 0.2450086),
+    (584, 17, 0, 0.262159202),
+    (642, 18, 0, 0.28051034614),
+    (706, 19, 0, 0.30014607037),
+    (776, 20, 0, 0.321156295296),
+    (852, 21, 0, 0.343637235966),
+    (936, 22, 0, 0.367691842484),
+    (1028, 23, 0, 0.393430271458),
+    (1130, 24, 0, 0.42097039046),
+    (1242, 25, 0, 0.450438317792),
+    (1366, 26, 0, 0.481969000038),
+    (1502, 27, 0, 0.51570683004),
+    (1652, 28, 0, 0.551806308143),
+    (1816, 29, 0, 0.590432749713),
+]"""
+
+
+@register_model("asr_w2l_conv_glu_encoder")
+class W2lConvGluEncoderModel(FairseqEncoderModel):
+    def __init__(self, encoder):
+        super().__init__(encoder)
+
+    @staticmethod
+    def add_args(parser):
+        """Add model-specific arguments to the parser."""
+        parser.add_argument(
+            "--input-feat-per-channel",
+            type=int,
+            metavar="N",
+            help="encoder input dimension per input channel",
+        )
+        parser.add_argument(
+            "--in-channels",
+            type=int,
+            metavar="N",
+            help="number of encoder input channels",
+        )
+        parser.add_argument(
+            "--conv-enc-config",
+            type=str,
+            metavar="EXPR",
+            help="""
+    an array of tuples each containing the configuration of one conv layer
+    [(out_channels, kernel_size, padding, dropout), ...]
+            """,
+        )
+
+    @classmethod
+    def build_model(cls, args, task):
+        """Build a new model instance."""
+        conv_enc_config = getattr(args, "conv_enc_config", default_conv_enc_config)
+        encoder = W2lConvGluEncoder(
+            vocab_size=len(task.target_dictionary),
+            input_feat_per_channel=args.input_feat_per_channel,
+            in_channels=args.in_channels,
+            conv_enc_config=eval(conv_enc_config),
+        )
+        return cls(encoder)
+
+    def get_normalized_probs(self, net_output, log_probs, sample=None):
+        lprobs = super().get_normalized_probs(net_output, log_probs, sample)
+        lprobs.batch_first = False
+        return lprobs
+
+
+class W2lConvGluEncoder(FairseqEncoder):
+    def __init__(
+        self, vocab_size, input_feat_per_channel, in_channels, conv_enc_config
+    ):
+        super().__init__(None)
+
+        self.input_dim = input_feat_per_channel
+        if in_channels != 1:
+            raise ValueError("only 1 input channel is currently supported")
+
+        self.conv_layers = nn.ModuleList()
+        self.linear_layers = nn.ModuleList()
+        self.dropouts = []
+        cur_channels = input_feat_per_channel
+
+        for out_channels, kernel_size, padding, dropout in conv_enc_config:
+            layer = nn.Conv1d(cur_channels, out_channels, kernel_size, padding=padding)
+            layer.weight.data.mul_(math.sqrt(3))  # match wav2letter init
+            self.conv_layers.append(nn.utils.weight_norm(layer))
+            self.dropouts.append(
+                FairseqDropout(dropout, module_name=self.__class__.__name__)
+            )
+            if out_channels % 2 != 0:
+                raise ValueError("odd # of out_channels is incompatible with GLU")
+            cur_channels = out_channels // 2  # halved by GLU
+
+        for out_channels in [2 * cur_channels, vocab_size]:
+            layer = nn.Linear(cur_channels, out_channels)
+            layer.weight.data.mul_(math.sqrt(3))
+            self.linear_layers.append(nn.utils.weight_norm(layer))
+            cur_channels = out_channels // 2
+
+    def forward(self, src_tokens, src_lengths, **kwargs):
+
+        """
+        src_tokens: padded tensor (B, T, C * feat)
+        src_lengths: tensor of original lengths of input utterances (B,)
+        """
+        B, T, _ = src_tokens.size()
+        x = src_tokens.transpose(1, 2).contiguous()  # (B, feat, T) assuming C == 1
+
+        for layer_idx in range(len(self.conv_layers)):
+            x = self.conv_layers[layer_idx](x)
+            x = F.glu(x, dim=1)
+            x = self.dropouts[layer_idx](x)
+
+        x = x.transpose(1, 2).contiguous()  # (B, T, 908)
+        x = self.linear_layers[0](x)
+        x = F.glu(x, dim=2)
+        x = self.dropouts[-1](x)
+        x = self.linear_layers[1](x)
+
+        assert x.size(0) == B
+        assert x.size(1) == T
+
+        encoder_out = x.transpose(0, 1)  # (T, B, vocab_size)
+
+        # need to debug this -- find a simpler/elegant way in pytorch APIs
+        encoder_padding_mask = (
+            torch.arange(T).view(1, T).expand(B, -1).to(x.device)
+            >= src_lengths.view(B, 1).expand(-1, T)
+        ).t()  # (B x T) -> (T x B)
+
+        return {
+            "encoder_out": encoder_out,  # (T, B, vocab_size)
+            "encoder_padding_mask": encoder_padding_mask,  # (T, B)
+        }
+
+    def reorder_encoder_out(self, encoder_out, new_order):
+        encoder_out["encoder_out"] = encoder_out["encoder_out"].index_select(
+            1, new_order
+        )
+        encoder_out["encoder_padding_mask"] = encoder_out[
+            "encoder_padding_mask"
+        ].index_select(1, new_order)
+        return encoder_out
+
+    def max_positions(self):
+        """Maximum input length supported by the encoder."""
+        return (1e6, 1e6)  # an arbitrary large number
+
+
+@register_model_architecture("asr_w2l_conv_glu_encoder", "w2l_conv_glu_enc")
+def w2l_conv_glu_enc(args):
+    args.input_feat_per_channel = getattr(args, "input_feat_per_channel", 80)
+    args.in_channels = getattr(args, "in_channels", 1)
+    args.conv_enc_config = getattr(args, "conv_enc_config", default_conv_enc_config)

examples/speech_recognition/tasks/__init__.py

@@ -0,0 +1,8 @@
+import importlib
+import os
+
+
+for file in os.listdir(os.path.dirname(__file__)):
+    if file.endswith(".py") and not file.startswith("_"):
+        task_name = file[: file.find(".py")]
+        importlib.import_module("examples.speech_recognition.tasks." + task_name)

examples/speech_recognition/tasks/speech_recognition.py

@@ -0,0 +1,157 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import json
+import os
+import re
+import sys
+
+import torch
+from examples.speech_recognition.data import AsrDataset
+from examples.speech_recognition.data.replabels import replabel_symbol
+from fairseq.data import Dictionary
+from fairseq.tasks import LegacyFairseqTask, register_task
+
+
+def get_asr_dataset_from_json(data_json_path, tgt_dict):
+    """
+    Parse data json and create dataset.
+    See scripts/asr_prep_json.py which pack json from raw files
+
+    Json example:
+    {
+    "utts": {
+        "4771-29403-0025": {
+            "input": {
+                "length_ms": 170,
+                "path": "/tmp/file1.flac"
+            },
+            "output": {
+                "text": "HELLO \n",
+                "token": "HE LLO",
+                "tokenid": "4815, 861"
+            }
+        },
+        "1564-142299-0096": {
+            ...
+        }
+    }
+    """
+    if not os.path.isfile(data_json_path):
+        raise FileNotFoundError("Dataset not found: {}".format(data_json_path))
+    with open(data_json_path, "rb") as f:
+        data_samples = json.load(f)["utts"]
+        assert len(data_samples) != 0
+        sorted_samples = sorted(
+            data_samples.items(),
+            key=lambda sample: int(sample[1]["input"]["length_ms"]),
+            reverse=True,
+        )
+        aud_paths = [s[1]["input"]["path"] for s in sorted_samples]
+        ids = [s[0] for s in sorted_samples]
+        speakers = []
+        for s in sorted_samples:
+            m = re.search("(.+?)-(.+?)-(.+?)", s[0])
+            speakers.append(m.group(1) + "_" + m.group(2))
+        frame_sizes = [s[1]["input"]["length_ms"] for s in sorted_samples]
+        tgt = [
+            [int(i) for i in s[1]["output"]["tokenid"].split(", ")]
+            for s in sorted_samples
+        ]
+        # append eos
+        tgt = [[*t, tgt_dict.eos()] for t in tgt]
+        return AsrDataset(aud_paths, frame_sizes, tgt, tgt_dict, ids, speakers)
+
+
+@register_task("speech_recognition")
+class SpeechRecognitionTask(LegacyFairseqTask):
+    """
+    Task for training speech recognition model.
+    """
+
+    @staticmethod
+    def add_args(parser):
+        """Add task-specific arguments to the parser."""
+        parser.add_argument("data", help="path to data directory")
+        parser.add_argument(
+            "--silence-token", default="\u2581", help="token for silence (used by w2l)"
+        )
+        parser.add_argument(
+            "--max-source-positions",
+            default=sys.maxsize,
+            type=int,
+            metavar="N",
+            help="max number of frames in the source sequence",
+        )
+        parser.add_argument(
+            "--max-target-positions",
+            default=1024,
+            type=int,
+            metavar="N",
+            help="max number of tokens in the target sequence",
+        )
+
+    def __init__(self, args, tgt_dict):
+        super().__init__(args)
+        self.tgt_dict = tgt_dict
+
+    @classmethod
+    def setup_task(cls, args, **kwargs):
+        """Setup the task (e.g., load dictionaries)."""
+        dict_path = os.path.join(args.data, "dict.txt")
+        if not os.path.isfile(dict_path):
+            raise FileNotFoundError("Dict not found: {}".format(dict_path))
+        tgt_dict = Dictionary.load(dict_path)
+
+        if args.criterion == "ctc_loss":
+            tgt_dict.add_symbol("<ctc_blank>")
+        elif args.criterion == "asg_loss":
+            for i in range(1, args.max_replabel + 1):
+                tgt_dict.add_symbol(replabel_symbol(i))
+
+        print("| dictionary: {} types".format(len(tgt_dict)))
+        return cls(args, tgt_dict)
+
+    def load_dataset(self, split, combine=False, **kwargs):
+        """Load a given dataset split.
+
+        Args:
+            split (str): name of the split (e.g., train, valid, test)
+        """
+        data_json_path = os.path.join(self.args.data, "{}.json".format(split))
+        self.datasets[split] = get_asr_dataset_from_json(data_json_path, self.tgt_dict)
+
+    def build_generator(self, models, args, **unused):
+        w2l_decoder = getattr(args, "w2l_decoder", None)
+        if w2l_decoder == "viterbi":
+            from examples.speech_recognition.w2l_decoder import W2lViterbiDecoder
+
+            return W2lViterbiDecoder(args, self.target_dictionary)
+        elif w2l_decoder == "kenlm":
+            from examples.speech_recognition.w2l_decoder import W2lKenLMDecoder
+
+            return W2lKenLMDecoder(args, self.target_dictionary)
+        elif w2l_decoder == "fairseqlm":
+            from examples.speech_recognition.w2l_decoder import W2lFairseqLMDecoder
+
+            return W2lFairseqLMDecoder(args, self.target_dictionary)
+        else:
+            return super().build_generator(models, args)
+
+    @property
+    def target_dictionary(self):
+        """Return the :class:`~fairseq.data.Dictionary` for the language
+        model."""
+        return self.tgt_dict
+
+    @property
+    def source_dictionary(self):
+        """Return the source :class:`~fairseq.data.Dictionary` (if applicable
+        for this task)."""
+        return None
+
+    def max_positions(self):
+        """Return the max speech and sentence length allowed by the task."""
+        return (self.args.max_source_positions, self.args.max_target_positions)

examples/speech_recognition/utils/wer_utils.py

@@ -0,0 +1,381 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import re
+from collections import deque
+from enum import Enum
+
+import numpy as np
+
+
+"""
+    Utility modules for computation of Word Error Rate,
+    Alignments, as well as more granular metrics like
+    deletion, insersion and substitutions.
+"""
+
+
+class Code(Enum):
+    match = 1
+    substitution = 2
+    insertion = 3
+    deletion = 4
+
+
+class Token(object):
+    def __init__(self, lbl="", st=np.nan, en=np.nan):
+        if np.isnan(st):
+            self.label, self.start, self.end = "", 0.0, 0.0
+        else:
+            self.label, self.start, self.end = lbl, st, en
+
+
+class AlignmentResult(object):
+    def __init__(self, refs, hyps, codes, score):
+        self.refs = refs  # std::deque<int>
+        self.hyps = hyps  # std::deque<int>
+        self.codes = codes  # std::deque<Code>
+        self.score = score  # float
+
+
+def coordinate_to_offset(row, col, ncols):
+    return int(row * ncols + col)
+
+
+def offset_to_row(offset, ncols):
+    return int(offset / ncols)
+
+
+def offset_to_col(offset, ncols):
+    return int(offset % ncols)
+
+
+def trimWhitespace(str):
+    return re.sub(" +", " ", re.sub(" *$", "", re.sub("^ *", "", str)))
+
+
+def str2toks(str):
+    pieces = trimWhitespace(str).split(" ")
+    toks = []
+    for p in pieces:
+        toks.append(Token(p, 0.0, 0.0))
+    return toks
+
+
+class EditDistance(object):
+    def __init__(self, time_mediated):
+        self.time_mediated_ = time_mediated
+        self.scores_ = np.nan  # Eigen::Matrix<float, Eigen::Dynamic, Eigen::Dynamic>
+        self.backtraces_ = (
+            np.nan
+        )  # Eigen::Matrix<size_t, Eigen::Dynamic, Eigen::Dynamic> backtraces_;
+        self.confusion_pairs_ = {}
+
+    def cost(self, ref, hyp, code):
+        if self.time_mediated_:
+            if code == Code.match:
+                return abs(ref.start - hyp.start) + abs(ref.end - hyp.end)
+            elif code == Code.insertion:
+                return hyp.end - hyp.start
+            elif code == Code.deletion:
+                return ref.end - ref.start
+            else:  # substitution
+                return abs(ref.start - hyp.start) + abs(ref.end - hyp.end) + 0.1
+        else:
+            if code == Code.match:
+                return 0
+            elif code == Code.insertion or code == Code.deletion:
+                return 3
+            else:  # substitution
+                return 4
+
+    def get_result(self, refs, hyps):
+        res = AlignmentResult(refs=deque(), hyps=deque(), codes=deque(), score=np.nan)
+
+        num_rows, num_cols = self.scores_.shape
+        res.score = self.scores_[num_rows - 1, num_cols - 1]
+
+        curr_offset = coordinate_to_offset(num_rows - 1, num_cols - 1, num_cols)
+
+        while curr_offset != 0:
+            curr_row = offset_to_row(curr_offset, num_cols)
+            curr_col = offset_to_col(curr_offset, num_cols)
+
+            prev_offset = self.backtraces_[curr_row, curr_col]
+
+            prev_row = offset_to_row(prev_offset, num_cols)
+            prev_col = offset_to_col(prev_offset, num_cols)
+
+            res.refs.appendleft(curr_row - 1)  # Note: this was .push_front() in C++
+            res.hyps.appendleft(curr_col - 1)
+            if curr_row - 1 == prev_row and curr_col == prev_col:
+                res.codes.appendleft(Code.deletion)
+            elif curr_row == prev_row and curr_col - 1 == prev_col:
+                res.codes.appendleft(Code.insertion)
+            else:
+                # assert(curr_row - 1 == prev_row and curr_col - 1 == prev_col)
+                ref_str = refs[res.refs[0]].label
+                hyp_str = hyps[res.hyps[0]].label
+
+                if ref_str == hyp_str:
+                    res.codes.appendleft(Code.match)
+                else:
+                    res.codes.appendleft(Code.substitution)
+
+                    confusion_pair = "%s -> %s" % (ref_str, hyp_str)
+                    if confusion_pair not in self.confusion_pairs_:
+                        self.confusion_pairs_[confusion_pair] = 1
+                    else:
+                        self.confusion_pairs_[confusion_pair] += 1
+
+            curr_offset = prev_offset
+
+        return res
+
+    def align(self, refs, hyps):
+        if len(refs) == 0 and len(hyps) == 0:
+            return np.nan
+
+        # NOTE: we're not resetting the values in these matrices because every value
+        # will be overridden in the loop below. If this assumption doesn't hold,
+        # be sure to set all entries in self.scores_ and self.backtraces_ to 0.
+        self.scores_ = np.zeros((len(refs) + 1, len(hyps) + 1))
+        self.backtraces_ = np.zeros((len(refs) + 1, len(hyps) + 1))
+
+        num_rows, num_cols = self.scores_.shape
+
+        for i in range(num_rows):
+            for j in range(num_cols):
+                if i == 0 and j == 0:
+                    self.scores_[i, j] = 0.0
+                    self.backtraces_[i, j] = 0
+                    continue
+
+                if i == 0:
+                    self.scores_[i, j] = self.scores_[i, j - 1] + self.cost(
+                        None, hyps[j - 1], Code.insertion
+                    )
+                    self.backtraces_[i, j] = coordinate_to_offset(i, j - 1, num_cols)
+                    continue
+
+                if j == 0:
+                    self.scores_[i, j] = self.scores_[i - 1, j] + self.cost(
+                        refs[i - 1], None, Code.deletion
+                    )
+                    self.backtraces_[i, j] = coordinate_to_offset(i - 1, j, num_cols)
+                    continue
+
+                # Below here both i and j are greater than 0
+                ref = refs[i - 1]
+                hyp = hyps[j - 1]
+                best_score = self.scores_[i - 1, j - 1] + (
+                    self.cost(ref, hyp, Code.match)
+                    if (ref.label == hyp.label)
+                    else self.cost(ref, hyp, Code.substitution)
+                )
+
+                prev_row = i - 1
+                prev_col = j - 1
+                ins = self.scores_[i, j - 1] + self.cost(None, hyp, Code.insertion)
+                if ins < best_score:
+                    best_score = ins
+                    prev_row = i
+                    prev_col = j - 1
+
+                delt = self.scores_[i - 1, j] + self.cost(ref, None, Code.deletion)
+                if delt < best_score:
+                    best_score = delt
+                    prev_row = i - 1
+                    prev_col = j
+
+                self.scores_[i, j] = best_score
+                self.backtraces_[i, j] = coordinate_to_offset(
+                    prev_row, prev_col, num_cols
+                )
+
+        return self.get_result(refs, hyps)
+
+
+class WERTransformer(object):
+    def __init__(self, hyp_str, ref_str, verbose=True):
+        self.ed_ = EditDistance(False)
+        self.id2oracle_errs_ = {}
+        self.utts_ = 0
+        self.words_ = 0
+        self.insertions_ = 0
+        self.deletions_ = 0
+        self.substitutions_ = 0
+
+        self.process(["dummy_str", hyp_str, ref_str])
+
+        if verbose:
+            print("'%s' vs '%s'" % (hyp_str, ref_str))
+            self.report_result()
+
+    def process(self, input):  # std::vector<std::string>&& input
+        if len(input) < 3:
+            print(
+                "Input must be of the form <id> ... <hypo> <ref> , got ",
+                len(input),
+                " inputs:",
+            )
+            return None
+
+        # Align
+        # std::vector<Token> hyps;
+        # std::vector<Token> refs;
+
+        hyps = str2toks(input[-2])
+        refs = str2toks(input[-1])
+
+        alignment = self.ed_.align(refs, hyps)
+        if alignment is None:
+            print("Alignment is null")
+            return np.nan
+
+        # Tally errors
+        ins = 0
+        dels = 0
+        subs = 0
+        for code in alignment.codes:
+            if code == Code.substitution:
+                subs += 1
+            elif code == Code.insertion:
+                ins += 1
+            elif code == Code.deletion:
+                dels += 1
+
+        # Output
+        row = input
+        row.append(str(len(refs)))
+        row.append(str(ins))
+        row.append(str(dels))
+        row.append(str(subs))
+        # print(row)
+
+        # Accumulate
+        kIdIndex = 0
+        kNBestSep = "/"
+
+        pieces = input[kIdIndex].split(kNBestSep)
+
+        if len(pieces) == 0:
+            print(
+                "Error splitting ",
+                input[kIdIndex],
+                " on '",
+                kNBestSep,
+                "', got empty list",
+            )
+            return np.nan
+
+        id = pieces[0]
+        if id not in self.id2oracle_errs_:
+            self.utts_ += 1
+            self.words_ += len(refs)
+            self.insertions_ += ins
+            self.deletions_ += dels
+            self.substitutions_ += subs
+            self.id2oracle_errs_[id] = [ins, dels, subs]
+        else:
+            curr_err = ins + dels + subs
+            prev_err = np.sum(self.id2oracle_errs_[id])
+            if curr_err < prev_err:
+                self.id2oracle_errs_[id] = [ins, dels, subs]
+
+        return 0
+
+    def report_result(self):
+        # print("----------  Summary ---------------")
+        if self.words_ == 0:
+            print("No words counted")
+            return
+
+        # 1-best
+        best_wer = (
+            100.0
+            * (self.insertions_ + self.deletions_ + self.substitutions_)
+            / self.words_
+        )
+
+        print(
+            "\tWER = %0.2f%% (%i utts, %i words, %0.2f%% ins, "
+            "%0.2f%% dels, %0.2f%% subs)"
+            % (
+                best_wer,
+                self.utts_,
+                self.words_,
+                100.0 * self.insertions_ / self.words_,
+                100.0 * self.deletions_ / self.words_,
+                100.0 * self.substitutions_ / self.words_,
+            )
+        )
+
+    def wer(self):
+        if self.words_ == 0:
+            wer = np.nan
+        else:
+            wer = (
+                100.0
+                * (self.insertions_ + self.deletions_ + self.substitutions_)
+                / self.words_
+            )
+        return wer
+
+    def stats(self):
+        if self.words_ == 0:
+            stats = {}
+        else:
+            wer = (
+                100.0
+                * (self.insertions_ + self.deletions_ + self.substitutions_)
+                / self.words_
+            )
+            stats = dict(
+                {
+                    "wer": wer,
+                    "utts": self.utts_,
+                    "numwords": self.words_,
+                    "ins": self.insertions_,
+                    "dels": self.deletions_,
+                    "subs": self.substitutions_,
+                    "confusion_pairs": self.ed_.confusion_pairs_,
+                }
+            )
+        return stats
+
+
+def calc_wer(hyp_str, ref_str):
+    t = WERTransformer(hyp_str, ref_str, verbose=0)
+    return t.wer()
+
+
+def calc_wer_stats(hyp_str, ref_str):
+    t = WERTransformer(hyp_str, ref_str, verbose=0)
+    return t.stats()
+
+
+def get_wer_alignment_codes(hyp_str, ref_str):
+    """
+    INPUT: hypothesis string, reference string
+    OUTPUT: List of alignment codes (intermediate results from WER computation)
+    """
+    t = WERTransformer(hyp_str, ref_str, verbose=0)
+    return t.ed_.align(str2toks(ref_str), str2toks(hyp_str)).codes
+
+
+def merge_counts(x, y):
+    # Merge two hashes which have 'counts' as their values
+    # This can be used for example to merge confusion pair counts
+    #   conf_pairs = merge_counts(conf_pairs, stats['confusion_pairs'])
+    for k, v in y.items():
+        if k not in x:
+            x[k] = 0
+        x[k] += v
+    return x

examples/speech_recognition/w2l_decoder.py

@@ -0,0 +1,453 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""
+Wav2letter decoders.
+"""
+
+import gc
+import pdb
+import itertools as it
+import os.path as osp
+import warnings
+from collections import deque, namedtuple
+
+import numpy as np
+import torch
+from examples.speech_recognition.data.replabels import unpack_replabels
+from fairseq import tasks, pdb
+from fairseq.utils import apply_to_sample
+
+
+try:
+    from wav2letter.common import create_word_dict, load_words
+    from wav2letter.criterion import CpuViterbiPath, get_data_ptr_as_bytes
+    from wav2letter.decoder import (
+        CriterionType,
+        DecoderOptions,
+        KenLM,
+        LM,
+        LMState,
+        SmearingMode,
+        Trie,
+        LexiconDecoder,
+    )
+except:
+    warnings.warn(
+        "wav2letter python bindings are required to use this functionality. Please install from https://github.com/facebookresearch/wav2letter/wiki/Python-bindings"
+    )
+    LM = object
+    LMState = object
+
+
+class W2lDecoder(object):
+    def __init__(self, args, tgt_dict):
+        self.tgt_dict = tgt_dict
+        self.vocab_size = len(tgt_dict)
+        self.nbest = args.nbest
+
+        # criterion-specific init
+        if args.criterion == "ctc":
+            self.criterion_type = "ctc"
+            self.blank = (
+                tgt_dict.index("<ctc_blank>")
+                if "<ctc_blank>" in tgt_dict.indices
+                else tgt_dict.bos()
+            )
+            self.asg_transitions = None
+        elif args.criterion == "asg_loss":
+            self.criterion_type = CriterionType.ASG
+            self.blank = -1
+            self.asg_transitions = args.asg_transitions
+            self.max_replabel = args.max_replabel
+            assert len(self.asg_transitions) == self.vocab_size ** 2
+        else:
+            raise RuntimeError(f"unknown criterion: {args.criterion}")
+
+    def generate(self, models, sample, **unused):
+        """Generate a batch of inferences."""
+        # model.forward normally channels prev_output_tokens into the decoder
+        # separately, but SequenceGenerator directly calls model.encoder
+        encoder_input = {
+            k: v for k, v in sample["net_input"].items() if k != "prev_output_tokens"
+        }
+        emissions = self.get_emissions(models, encoder_input)
+        return self.decode(emissions)
+
+    def get_emissions(self, models, encoder_input):
+        """Run encoder and normalize emissions"""
+        # encoder_out = models[0].encoder(**encoder_input)
+        encoder_out = models[0](**encoder_input)
+        if self.criterion_type == "ctc":
+            emissions = models[0].get_normalized_probs(encoder_out, log_probs=True)
+        elif self.criterion_type == CriterionType.ASG:
+            emissions = encoder_out["encoder_out"]
+        return emissions.transpose(0, 1).float().cpu().contiguous()
+
+    def get_tokens(self, idxs):
+        """Normalize tokens by handling CTC blank, ASG replabels, etc."""
+        idxs = (g[0] for g in it.groupby(idxs))
+        if self.criterion_type == "ctc":
+            idxs = filter(lambda x: x != self.blank, idxs)
+        elif self.criterion_type == CriterionType.ASG:
+            idxs = filter(lambda x: x >= 0, idxs)
+            idxs = unpack_replabels(list(idxs), self.tgt_dict, self.max_replabel)
+        return torch.LongTensor(list(idxs))
+
+
+class W2lViterbiDecoder(W2lDecoder):
+    def __init__(self, args, tgt_dict):
+        super().__init__(args, tgt_dict)
+
+    def decode(self, emissions):
+        B, T, N = emissions.size()
+        results = []
+        """
+        hypos = []
+        if self.asg_transitions is None:
+            transitions = torch.FloatTensor(N, N).zero_()
+        else:
+            transitions = torch.FloatTensor(self.asg_transitions).view(N, N)
+        viterbi_path = torch.IntTensor(B, T)
+        workspace = torch.ByteTensor(CpuViterbiPath.get_workspace_size(B, T, N))
+        CpuViterbiPath.compute(
+            B,
+            T,
+            N,
+            get_data_ptr_as_bytes(emissions),
+            get_data_ptr_as_bytes(transitions),
+            get_data_ptr_as_bytes(viterbi_path),
+            get_data_ptr_as_bytes(workspace),
+        )
+        return [
+            [{"tokens": self.get_tokens(viterbi_path[b].tolist()), "score": 0}]
+            for b in range(B)
+        ]
+        """
+        for b in range(B):
+            am_scores = emissions[b]
+            tokens = am_scores.argmax(dim=-1)
+            ids = []
+            for i in range(T):
+                if tokens[i].item() != self.tgt_dict.bos():
+                    if i == 0:
+                        ids.append(tokens[i].item())
+                    elif tokens[i].item() != tokens[i-1].item():
+                        ids.append(tokens[i].item())
+            results.append([{"tokens": torch.LongTensor(ids), "score": 0.0}])
+        return results
+
+
+
+
+class W2lKenLMDecoder(W2lDecoder):
+    def __init__(self, args, tgt_dict):
+        super().__init__(args, tgt_dict)
+
+        self.silence = (
+            tgt_dict.index("<ctc_blank>")
+            if "<ctc_blank>" in tgt_dict.indices
+            else tgt_dict.bos()
+        )
+        self.lexicon = load_words(args.lexicon)
+        self.word_dict = create_word_dict(self.lexicon)
+        self.unk_word = self.word_dict.get_index("<unk>")
+
+        self.lm = KenLM(args.kenlm_model, self.word_dict)
+        self.trie = Trie(self.vocab_size, self.silence)
+
+        start_state = self.lm.start(False)
+        for i, (word, spellings) in enumerate(self.lexicon.items()):
+            word_idx = self.word_dict.get_index(word)
+            _, score = self.lm.score(start_state, word_idx)
+            for spelling in spellings:
+                spelling_idxs = [tgt_dict.index(token) for token in spelling]
+                assert (
+                    tgt_dict.unk() not in spelling_idxs
+                ), f"{spelling} {spelling_idxs}"
+                self.trie.insert(spelling_idxs, word_idx, score)
+        self.trie.smear(SmearingMode.MAX)
+
+        self.decoder_opts = DecoderOptions(
+            args.beam,
+            int(getattr(args, "beam_size_token", len(tgt_dict))),
+            args.beam_threshold,
+            args.lm_weight,
+            args.word_score,
+            args.unk_weight,
+            args.sil_weight,
+            0,
+            False,
+            self.criterion_type,
+        )
+
+        if self.asg_transitions is None:
+            N = 768
+            # self.asg_transitions = torch.FloatTensor(N, N).zero_()
+            self.asg_transitions = []
+
+        self.decoder = LexiconDecoder(
+            self.decoder_opts,
+            self.trie,
+            self.lm,
+            self.silence,
+            self.blank,
+            self.unk_word,
+            self.asg_transitions,
+            False,
+        )
+
+    def decode(self, emissions):
+        B, T, N = emissions.size()
+        hypos = []
+        for b in range(B):
+            emissions_ptr = emissions.data_ptr() + 4 * b * emissions.stride(0)
+            results = self.decoder.decode(emissions_ptr, T, N)
+
+            nbest_results = results[: self.nbest]
+            hypos.append(
+                [
+                    {
+                        "tokens": self.get_tokens(result.tokens),
+                        "score": result.score,
+                        "words": [
+                            self.word_dict.get_entry(x) for x in result.words if x >= 0
+                        ],
+                    }
+                    for result in nbest_results
+                ]
+            )
+        return hypos
+
+
+FairseqLMState = namedtuple("FairseqLMState", ["prefix", "incremental_state", "probs"])
+
+
+class FairseqLM(LM):
+    def __init__(self, dictionary, model):
+        LM.__init__(self)
+        self.dictionary = dictionary
+        self.model = model
+        self.unk = self.dictionary.unk()
+
+        self.save_incremental = False  # this currently does not work properly
+        self.max_cache = 20_000
+
+        model.cuda()
+        model.eval()
+        model.make_generation_fast_()
+
+        self.states = {}
+        self.stateq = deque()
+
+    def start(self, start_with_nothing):
+        state = LMState()
+        prefix = torch.LongTensor([[self.dictionary.eos()]])
+        incremental_state = {} if self.save_incremental else None
+        with torch.no_grad():
+            res = self.model(prefix.cuda(), incremental_state=incremental_state)
+            probs = self.model.get_normalized_probs(res, log_probs=True, sample=None)
+
+        if incremental_state is not None:
+            incremental_state = apply_to_sample(lambda x: x.cpu(), incremental_state)
+        self.states[state] = FairseqLMState(
+            prefix.numpy(), incremental_state, probs[0, -1].cpu().numpy()
+        )
+        self.stateq.append(state)
+
+        return state
+
+    def score(self, state: LMState, token_index: int, no_cache: bool = False):
+        """
+        Evaluate language model based on the current lm state and new word
+        Parameters:
+        -----------
+        state: current lm state
+        token_index: index of the word
+                     (can be lexicon index then you should store inside LM the
+                      mapping between indices of lexicon and lm, or lm index of a word)
+
+        Returns:
+        --------
+        (LMState, float): pair of (new state, score for the current word)
+        """
+        curr_state = self.states[state]
+
+        def trim_cache(targ_size):
+            while len(self.stateq) > targ_size:
+                rem_k = self.stateq.popleft()
+                rem_st = self.states[rem_k]
+                rem_st = FairseqLMState(rem_st.prefix, None, None)
+                self.states[rem_k] = rem_st
+
+        if curr_state.probs is None:
+            new_incremental_state = (
+                curr_state.incremental_state.copy()
+                if curr_state.incremental_state is not None
+                else None
+            )
+            with torch.no_grad():
+                if new_incremental_state is not None:
+                    new_incremental_state = apply_to_sample(
+                        lambda x: x.cuda(), new_incremental_state
+                    )
+                elif self.save_incremental:
+                    new_incremental_state = {}
+
+                res = self.model(
+                    torch.from_numpy(curr_state.prefix).cuda(),
+                    incremental_state=new_incremental_state,
+                )
+                probs = self.model.get_normalized_probs(
+                    res, log_probs=True, sample=None
+                )
+
+                if new_incremental_state is not None:
+                    new_incremental_state = apply_to_sample(
+                        lambda x: x.cpu(), new_incremental_state
+                    )
+
+                curr_state = FairseqLMState(
+                    curr_state.prefix, new_incremental_state, probs[0, -1].cpu().numpy()
+                )
+
+            if not no_cache:
+                self.states[state] = curr_state
+                self.stateq.append(state)
+
+        score = curr_state.probs[token_index].item()
+
+        trim_cache(self.max_cache)
+
+        outstate = state.child(token_index)
+        if outstate not in self.states and not no_cache:
+            prefix = np.concatenate(
+                [curr_state.prefix, torch.LongTensor([[token_index]])], -1
+            )
+            incr_state = curr_state.incremental_state
+
+            self.states[outstate] = FairseqLMState(prefix, incr_state, None)
+
+        if token_index == self.unk:
+            score = float("-inf")
+
+        return outstate, score
+
+    def finish(self, state: LMState):
+        """
+        Evaluate eos for language model based on the current lm state
+
+        Returns:
+        --------
+        (LMState, float): pair of (new state, score for the current word)
+        """
+        return self.score(state, self.dictionary.eos())
+
+    def empty_cache(self):
+        self.states = {}
+        self.stateq = deque()
+        gc.collect()
+
+
+class W2lFairseqLMDecoder(W2lDecoder):
+    def __init__(self, args, tgt_dict):
+        super().__init__(args, tgt_dict)
+
+        self.silence = tgt_dict.bos()
+
+        self.unit_lm = getattr(args, "unit_lm", False)
+
+        self.lexicon = load_words(args.lexicon) if args.lexicon else None
+        self.idx_to_wrd = {}
+
+        checkpoint = torch.load(args.kenlm_model, map_location="cpu")
+        lm_args = checkpoint["args"]
+        lm_args.data = osp.dirname(args.kenlm_model)
+        print(lm_args)
+        task = tasks.setup_task(lm_args)
+        model = task.build_model(lm_args)
+        model.load_state_dict(checkpoint["model"], strict=False)
+
+        self.trie = Trie(self.vocab_size, self.silence)
+
+        self.word_dict = task.dictionary
+        self.unk_word = self.word_dict.unk()
+        self.lm = FairseqLM(self.word_dict, model)
+
+        self.decoder_opts = DecoderOptions(
+            args.beam,
+            int(getattr(args, "beam_size_token", len(tgt_dict))),
+            args.beam_threshold,
+            args.lm_weight,
+            args.word_score,
+            args.unk_weight,
+            args.sil_weight,
+            0,
+            False,
+            self.criterion_type,
+        )
+
+        if self.lexicon:
+            start_state = self.lm.start(False)
+            for i, (word, spellings) in enumerate(self.lexicon.items()):
+                if self.unit_lm:
+                    word_idx = i
+                    self.idx_to_wrd[i] = word
+                    score = 0
+                else:
+                    word_idx = self.word_dict.index(word)
+                    _, score = self.lm.score(start_state, word_idx, no_cache=True)
+
+                for spelling in spellings:
+                    spelling_idxs = [tgt_dict.index(token) for token in spelling]
+                    assert (
+                        tgt_dict.unk() not in spelling_idxs
+                    ), f"{spelling} {spelling_idxs}"
+                    self.trie.insert(spelling_idxs, word_idx, score)
+            self.trie.smear(SmearingMode.MAX)
+
+            self.decoder = LexiconDecoder(
+                self.decoder_opts,
+                self.trie,
+                self.lm,
+                self.silence,
+                self.blank,
+                self.unk_word,
+                [],
+                self.unit_lm,
+            )
+        else:
+            from wav2letter.decoder import LexiconFreeDecoder
+            self.decoder = LexiconFreeDecoder(
+                self.decoder_opts, self.lm, self.silence, self.blank, []
+            )
+
+    def decode(self, emissions):
+        B, T, N = emissions.size()
+        hypos = []
+
+        def idx_to_word(idx):
+            if self.unit_lm:
+                return self.idx_to_wrd[idx]
+            else:
+                return self.word_dict[idx]
+
+        def make_hypo(result):
+            hypo = {"tokens": self.get_tokens(result.tokens), "score": result.score}
+            if self.lexicon:
+                hypo["words"] = [idx_to_word(x) for x in result.words if x >= 0]
+            return hypo
+
+        for b in range(B):
+            emissions_ptr = emissions.data_ptr() + 4 * b * emissions.stride(0)
+            results = self.decoder.decode(emissions_ptr, T, N)
+
+            nbest_results = results[: self.nbest]
+            hypos.append([make_hypo(result) for result in nbest_results])
+            self.lm.empty_cache()
+
+        return hypos

examples/unispeech/adjust_sample_rate.py

@@ -0,0 +1,60 @@
+import argparse
+import os
+import librosa
+import soundfile as sf
+
+from pydub import AudioSegment
+
+
+def get_parser():
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        '--wav-path', type=str
+    )
+    parser.add_argument(
+        '--dest-path', type=str
+    )
+    parser.add_argument(
+        '--input', type=str
+    )
+    parser.add_argument(
+        '--output', type=str
+    )
+
+    return parser
+
+
+def main(args):
+    os.makedirs(args.dest_path, exist_ok=True)
+
+    f = open(args.input)
+    data = f.readlines()
+    f.close()
+
+    wf = open(args.output, 'w')
+    wf.write(args.dest_path+"\n")
+    count = len(data)
+    for line in data:
+        wav_name = line.strip()
+        wav_file = os.path.join(args.wav_path, wav_name)
+        base_wav_name = os.path.splitext(wav_name)[0]
+        output_file = os.path.join(args.dest_path, base_wav_name+".wav")
+        if os.path.exists(wav_file) and not os.path.exists(output_file):
+            sound = AudioSegment.from_mp3(wav_file)
+            sound.export(os.path.join(args.dest_path, 'tmp.wav'), format='wav')
+            y, sr = librosa.load(os.path.join(args.dest_path, 'tmp.wav'), sr=16000)
+            sf.write(output_file, y, sr)
+            infos = sf.info(output_file)
+            frames = infos.frames
+            sr = infos.samplerate
+            wf.write("{}\t{}\t{}\n".format(base_wav_name+".wav", frames, sr))
+            count += 1
+        if count % 100 == 0:
+            print('process {} done'.format(count))
+
+    wf.close()
+
+if __name__ == "__main__":
+    parser = get_parser()
+    args = parser.parse_args()
+    main(args)

examples/unispeech/libri_labels.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python3
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""
+Helper script to pre-compute embeddings for a wav2letter++ dataset
+"""
+
+import argparse
+import os
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("tsv")
+    parser.add_argument("--output-dir", required=True)
+    parser.add_argument("--output-name", required=True)
+    args = parser.parse_args()
+
+    os.makedirs(args.output_dir, exist_ok=True)
+
+    transcriptions = {}
+
+    with open(args.tsv, "r") as tsv, open(
+        os.path.join(args.output_dir, args.output_name + ".ltr"), "w"
+    ) as ltr_out, open(
+        os.path.join(args.output_dir, args.output_name + ".wrd"), "w"
+    ) as wrd_out:
+        root = next(tsv).strip()
+        for line in tsv:
+            line = line.strip()
+            dir = os.path.dirname(line)
+            if dir not in transcriptions:
+                parts = dir.split(os.path.sep)
+                trans_path = f"{parts[-2]}-{parts[-1]}.trans.txt"
+                path = os.path.join(root, dir, trans_path)
+                assert os.path.exists(path)
+                texts = {}
+                with open(path, "r") as trans_f:
+                    for tline in trans_f:
+                        items = tline.strip().split()
+                        texts[items[0]] = " ".join(items[1:])
+                transcriptions[dir] = texts
+            part = os.path.basename(line).split(".")[0]
+            assert part in transcriptions[dir]
+            print(transcriptions[dir][part], file=wrd_out)
+            print(
+                " ".join(list(transcriptions[dir][part].replace(" ", "|"))) + " |",
+                file=ltr_out,
+            )
+
+
+if __name__ == "__main__":
+    main()

examples/unispeech/scripts/continue_pretrain.sh

@@ -0,0 +1,11 @@
+model_path=YOUR_MODEL_PATH
+train_subset=pretrain_HOUR_16k
+valid_subset=valSeqs_1.0_uniform_new_version_16k
+WORLD_SIZE=8
+
+
+update_freq=2
+
+mkdir -p ${model_path}
+
+python train.py --distributed-world-size ${WORLD_SIZE} --distributed-port 0 examples/unispeech/data/LANG --save-dir ${model_path} --fp16 --num-workers 10 --task audio_pretraining --criterion wav2vec --arch unispeech --train-subset ${train_subset} --valid-subset ${valid_subset} --log-keys '["prob_perplexity","code_perplexity","temp"]' --quantize-targets --normalize --extractor-mode "layer_norm" --encoder-layers 24 --encoder-embed-dim 1024 --encoder-ffn-embed-dim 4096 --encoder-attention-heads 16 --final-dim 768 --layer-norm-first --conv-feature-layers '[(512, 10, 5)] + [(512, 3, 2)] * 4 + [(512,2,2)] * 2' --latent-vars 320 --latent-groups 2 --latent-temp '(2,0.1,0.999995)' --infonce --optimizer adam --adam-betas '(0.9,0.98)' --adam-eps 1e-06 --lr-scheduler polynomial_decay --total-num-update 100000 --lr 0.0002 --warmup-updates 10000 --mask-length 10 --mask-prob 0.65 --mask-selection static --mask-other 0 --encoder-layerdrop 0.05 --dropout-input 0.1 --dropout-features 0.1 --feature-grad-mult 0.1 --loss-weights '[0.1, 0]' --conv-pos 128 --conv-pos-groups 16 --num-negatives 100 --cross-sample-negatives 0 --max-sample-size 250000 --min-sample-size 32000 --dropout 0.1 --attention-dropout 0.1 --weight-decay 0.01 --max-tokens 1000000 --max-update 100000 --skip-invalid-size-inputs-valid-test --ddp-backend no_c10d --update-freq ${update_freq} --pretrained-path PRETRAINED_MODEL_FROM_STAGE_1 --no-epoch-checkpoints --transpose --save-interval 4 --validate-interval 4

examples/unispeech/scripts/finetune.sh

@@ -0,0 +1,11 @@
+model_path=~/test
+pretrained_model=/datablob/users/v-chengw/commonvoice_model/ptmtls2_en1350.large.lr1e-3.64gpu.fgm0.1/checkpoint_best.pt
+train_subset=trainSeqs_1.0_uniform_new_version_16k
+valid_subset=valSeqs_1.0_uniform_new_version_16k
+
+mkdir -p ${model_path}
+WORLD_SIZE=4
+updata_freq=1
+
+
+python train.py --distributed-world-size $WORLD_SIZE --distributed-port 0 /datablob/users/v-chengw/data/commonvoice_20200622/resource/nl --save-dir ${model_path} --post-process word --train-subset ${train_subset} --valid-subset ${valid_subset} --no-epoch-checkpoints --best-checkpoint-metric uer --num-workers 4 --max-update 20000 --sentence-avg --task audio_pretraining --arch wav2vec_ctc --w2v-path ${pretrained_model} --labels ltr --apply-mask --mask-selection static --mask-other 0 --mask-length 10 --mask-prob 0.75 --layerdrop 0.1 --mask-channel-selection static --mask-channel-other 0 --mask-channel-length 64 --mask-channel-prob 0.25 --zero-infinity --feature-grad-mult 0.0 --freeze-finetune-updates 2000 --validate-after-updates 2000 --optimizer adam --adam-betas '(0.9, 0.98)' --adam-eps 1e-08 --lr 2e-05 --lr-scheduler tri_stage --warmup-steps 2000 --hold-steps 8000 --decay-steps 10000 --final-lr-scale 0.05 --activation-dropout 0.1  --dropout 0.1 --attention-dropout 0.1 --final-dropout 0.1 --dropout-input 0.1 --criterion ctc --max-tokens 1000000 --seed 1337 --log-format json --log-interval 100 --ddp-backend no_c10d --fp16 --update-freq ${updata_freq} --dict-path /datablob/users/v-chengw/data/commonvoice_20200622/common_voices_splits/nl/phonesMatches_reduced.json --save-interval 10 --validate-interval 10 --normalize

examples/unispeech/scripts/multilingal_large_pretrain.sh

@@ -0,0 +1,13 @@
+model_path=MODEL_PATH
+valid_subset=en/valid_16k
+WORLD_SIZE=NUM_OF_GPUS
+
+
+update_freq=$((64/$WORLD_SIZE))  #ngpu * update_freq = 64
+
+DISTRIBUTED_ARGS="--nproc_per_node $GPUS_PER_NODE --nnodes $NNODES --node_rank $NODE_RANK --master_addr $MASTER_ADDR --master_port $MASTER_PORT"
+
+
+mkdir -p ${model_path}
+
+python -m torch.distributed.launch $DISTRIBUTED_ARGS train.py --distributed-world-size ${WORLD_SIZE} --distributed-port 0 examples/unispeech/data --save-dir ${model_path} --fp16 --num-workers 10 --task audio_pretraining --criterion wav2vec_mtl --arch unispeech --extractor-mode "layer_norm" --encoder-layers 24 --encoder-embed-dim 1024 --encoder-ffn-embed-dim 4096 --encoder-attention-heads 16 --final-dim 768 --layer-norm-first --conv-bias --logit-temp 0.1 --train-subset en/pretrain_1350_16k,es/pretrain_168_16k_sep,fr/pretrain_353_16k_sep,it/pretrain_90_16k_sep --valid-subset ${valid_subset} --log-keys '["prob_perplexity","code_perplexity","temp"]' --quantize-targets --conv-feature-layers '[(512, 10, 5)] + [(512, 3, 2)] * 4 + [(512,2,2)] * 2' --latent-vars 320 --latent-groups 2 --latent-temp '(2,0.1,0.999995)' --infonce --optimizer adam --adam-betas '(0.9,0.98)' --adam-eps 1e-06 --lr-scheduler polynomial_decay --total-num-update 200000 --lr 0.001 --warmup-updates 25000 --mask-length 10 --mask-prob 0.5 --mask-selection static --mask-other 0 --encoder-layerdrop 0.0 --dropout-input 0.1 --dropout-features 0.1 --feature-grad-mult 1.0 --loss-weights '[0.1, 0]' --conv-pos 128 --conv-pos-groups 16 --num-negatives 100 --cross-sample-negatives 0 --max-sample-size 320000 --min-sample-size 32000 --dropout 0.1 --attention-dropout 0.1 --weight-decay 0.01 --max-tokens 1200000 --max-update 250000 --skip-invalid-size-inputs-valid-test --ddp-backend no_c10d --update-freq ${update_freq} --post-process word --labels ltr --dict-path examples/unispeech/data/en/vocab_sep.json --negatives-from-everywhere --mtlalpha 0.5 --replace-prob 0.5 --transpose --no-epoch-checkpoints --log-format json

examples/unispeech/scripts/one2one_large_pretrain_en1350.sh

@@ -0,0 +1,12 @@
+model_path=MODEL_PATH
+train_subset=pretrain_1350_16k
+valid_subset=valid_16k
+WORLD_SIZE=NUM_OF_GPUS
+
+
+update_freq=$((64/$WORLD_SIZE))  #ngpu * update_freq = 64
+DISTRIBUTED_ARGS="--nproc_per_node $GPUS_PER_NODE --nnodes $NNODES --node_rank $NODE_RANK --master_addr $MASTER_ADDR --master_port $MASTER_PORT"
+
+mkdir -p ${model_path}
+
+python -m torch.distributed.launch $DISTRIBUTED_ARGS train.py --distributed-world-size ${WORLD_SIZE} --distributed-port 0 examples/unispeech/data/en --save-dir ${model_path} --fp16 --num-workers 10 --task audio_pretraining --criterion wav2vec_mtl --arch unispeech --extractor-mode "layer_norm" --encoder-layers 24 --encoder-embed-dim 1024 --encoder-ffn-embed-dim 4096 --encoder-attention-heads 16 --final-dim 768 --layer-norm-first --conv-bias --logit-temp 0.1 --train-subset ${train_subset} --valid-subset ${valid_subset} --log-keys '["prob_perplexity","code_perplexity","temp"]' --quantize-targets --conv-feature-layers '[(512, 10, 5)] + [(512, 3, 2)] * 4 + [(512,2,2)] * 2' --latent-vars 320 --latent-groups 2 --latent-temp '(2,0.1,0.999995)' --infonce --optimizer adam --adam-betas '(0.9,0.98)' --adam-eps 1e-06 --lr-scheduler polynomial_decay --total-num-update 200000 --lr 0.001 --warmup-updates 25000 --mask-length 10 --mask-prob 0.5 --mask-selection static --mask-other 0 --encoder-layerdrop 0.0 --dropout-input 0.1 --dropout-features 0.1 --feature-grad-mult 1.0 --loss-weights '[0.1, 0]' --conv-pos 128 --conv-pos-groups 16 --num-negatives 100 --cross-sample-negatives 0 --max-sample-size 320000 --min-sample-size 32000 --dropout 0.1 --attention-dropout 0.1 --weight-decay 0.01 --max-tokens 1200000 --max-update 250000 --skip-invalid-size-inputs-valid-test --ddp-backend no_c10d --update-freq ${update_freq} --post-process word --labels ltr --dict-path examples/unispeech/data/en/vocab.json --negatives-from-everywhere --mtlalpha 0.5 --replace-prob 0.5 --transpose --no-epoch-checkpoints --log-format json

examples/unispeech/unispeech_manifest.py

@@ -0,0 +1,46 @@
+import argparse
+import os
+
+
+def get_parser():
+    parser = argparse.ArgumentParser()
+    
+    parser.add_argument(
+        'input', 
+        type=str,
+        help="input .tsv file"
+    )
+    parser.add_argument(
+        '--dest',
+        type=str,
+        help="output directory"
+    )
+
+    return parser
+
+
+def main(args):
+    wav_names = []
+    text = []
+    with open(args.input) as f:
+        f.readline()
+        for line in f:
+            items = line.strip().split("\t")
+            wav_names.append(items[1])
+            text.append(items[2])
+    base_name = os.path.basename(args.input)
+    file_name = os.path.splitext(base_name)[0]
+
+    with open(os.path.join(args.dest, file_name+'.list'), 'w') as f:
+        for name in wav_names:
+            f.write(name+"\n")
+
+    with open(os.path.join(args.dest, file_name+'.text'), 'w') as f:
+        for i in range(len(wav_names)):
+            f.write("{}\t{}\n".format(wav_names[i], text[i]))
+
+	
+if __name__ == "__main__":
+    parser = get_parser()
+    args = parser.parse_args()
+    main(args)

examples/unispeech/wav2vec_manifest.py

@@ -0,0 +1,76 @@
+#!/usr/bin/env python3
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+"""
+Data pre-processing: build vocabularies and binarize training data.
+"""
+
+import argparse
+import glob
+import os
+import random
+
+import soundfile
+
+
+def get_parser():
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "root", metavar="DIR", help="root directory containing flac files to index"
+    )
+    parser.add_argument(
+        "--valid-percent",
+        default=0.01,
+        type=float,
+        metavar="D",
+        help="percentage of data to use as validation set (between 0 and 1)",
+    )
+    parser.add_argument(
+        "--dest", default=".", type=str, metavar="DIR", help="output directory"
+    )
+    parser.add_argument(
+        "--ext", default="flac", type=str, metavar="EXT", help="extension to look for"
+    )
+    parser.add_argument("--seed", default=42, type=int, metavar="N", help="random seed")
+    parser.add_argument(
+        "--path-must-contain",
+        default=None,
+        type=str,
+        metavar="FRAG",
+        help="if set, path must contain this substring for a file to be included in the manifest",
+    )
+    return parser
+
+
+def main(args):
+    assert args.valid_percent >= 0 and args.valid_percent <= 1.0
+
+    dir_path = os.path.realpath(args.root)
+    search_path = os.path.join(dir_path, "**/*." + args.ext)
+    rand = random.Random(args.seed)
+
+    with open(os.path.join(args.dest, "train.tsv"), "w") as train_f, open(
+        os.path.join(args.dest, "valid.tsv"), "w"
+    ) as valid_f:
+        print(dir_path, file=train_f)
+        print(dir_path, file=valid_f)
+
+        for fname in glob.iglob(search_path, recursive=True):
+            file_path = os.path.realpath(fname)
+
+            if args.path_must_contain and args.path_must_contain not in file_path:
+                continue
+
+            frames = soundfile.info(fname).frames
+            dest = train_f if rand.random() > args.valid_percent else valid_f
+            print(
+                "{}\t{}".format(os.path.relpath(file_path, dir_path), frames), file=dest
+            )
+
+
+if __name__ == "__main__":
+    parser = get_parser()
+    args = parser.parse_args()
+    main(args)

fairseq/__init__.py

@@ -0,0 +1,41 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+"""isort:skip_file"""
+
+import os
+import sys
+
+try:
+    from .version import __version__  # noqa
+except ImportError:
+    version_txt = os.path.join(os.path.dirname(__file__), "version.txt")
+    with open(version_txt) as f:
+        __version__ = f.read().strip()
+
+__all__ = ["pdb"]
+
+# backwards compatibility to support `from fairseq.meters import AverageMeter`
+from fairseq.logging import meters, metrics, progress_bar  # noqa
+
+sys.modules["fairseq.meters"] = meters
+sys.modules["fairseq.metrics"] = metrics
+sys.modules["fairseq.progress_bar"] = progress_bar
+
+# initialize hydra
+from fairseq.dataclass.initialize import hydra_init
+hydra_init()
+
+import fairseq.criterions  # noqa
+import fairseq.models  # noqa
+import fairseq.modules  # noqa
+import fairseq.optim  # noqa
+import fairseq.optim.lr_scheduler  # noqa
+import fairseq.pdb  # noqa
+import fairseq.scoring  # noqa
+import fairseq.tasks  # noqa
+import fairseq.token_generation_constraints  # noqa
+
+import fairseq.benchmark  # noqa
+import fairseq.model_parallel  # noqa

fairseq/benchmark/__init__.py

@@ -0,0 +1,7 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+# import models/tasks to register them
+from . import dummy_lm, dummy_masked_lm, dummy_model, dummy_mt  # noqa

fairseq/benchmark/dummy_lm.py

@@ -0,0 +1,125 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import logging
+
+import numpy as np
+import torch
+from fairseq.data import Dictionary, FairseqDataset
+from fairseq.tasks import LegacyFairseqTask, register_task
+
+
+logger = logging.getLogger(__name__)
+
+
+@register_task("dummy_lm")
+class DummyLMTask(LegacyFairseqTask):
+    @staticmethod
+    def add_args(parser):
+        """Add task-specific arguments to the parser."""
+        parser.add_argument("--dict-size", default=49996, type=int)
+        parser.add_argument("--dataset-size", default=100000, type=int)
+        parser.add_argument(
+            "--tokens-per-sample",
+            default=512,
+            type=int,
+            help="max number of total tokens over all segments "
+            "per sample for BERT dataset",
+        )
+        parser.add_argument("--add-bos-token", action="store_true", help="unused")
+        parser.add_argument(
+            "--max-target-positions",
+            default=None,
+            help="max number of tokens in the target sequence",
+        )
+
+    def __init__(self, args, dictionary):
+        super().__init__(args)
+        self.dictionary = dictionary
+        self.seed = args.seed
+
+        dictionary.pad_to_multiple_(8)  # often faster if divisible by 8
+
+        seq = torch.arange(args.tokens_per_sample + 1) + dictionary.pad() + 1
+
+        self.dummy_src = seq[:-1]
+        self.dummy_tgt = seq[1:]
+
+    @classmethod
+    def setup_task(cls, args, **kwargs):
+        """Setup the task. """
+        dictionary = Dictionary()
+        for i in range(args.dict_size):
+            dictionary.add_symbol("word{}".format(i))
+        logger.info("dictionary: {} types".format(len(dictionary)))
+        return cls(args, dictionary)
+
+    def load_dataset(self, split, epoch=1, combine=False, **kwargs):
+        """Load a given dataset split.
+        Args:
+            split (str): name of the split (e.g., train, valid, test)
+        """
+        if self.args.batch_size is not None:
+            bsz = self.args.batch_size
+        else:
+            bsz = max(1, self.args.max_tokens // self.args.tokens_per_sample)
+        self.datasets[split] = DummyDataset(
+            {
+                "id": 1,
+                "net_input": {
+                    "src_tokens": torch.stack([self.dummy_src for _ in range(bsz)]),
+                    "src_lengths": torch.full(
+                        (bsz,), self.args.tokens_per_sample, dtype=torch.long
+                    ),
+                },
+                "target": torch.stack([self.dummy_tgt for _ in range(bsz)]),
+                "nsentences": bsz,
+                "ntokens": bsz * self.args.tokens_per_sample,
+            },
+            num_items=self.args.dataset_size,
+            item_size=self.args.tokens_per_sample,
+        )
+
+    @property
+    def source_dictionary(self):
+        return self.dictionary
+
+    @property
+    def target_dictionary(self):
+        return self.dictionary
+
+
+class DummyDataset(FairseqDataset):
+    def __init__(self, batch, num_items, item_size):
+        super().__init__()
+        self.batch = batch
+        self.num_items = num_items
+        self.item_size = item_size
+
+    def __getitem__(self, index):
+        return index
+
+    def __len__(self):
+        return self.num_items
+
+    def collater(self, samples):
+        return self.batch
+
+    @property
+    def sizes(self):
+        return np.array([self.item_size] * self.num_items)
+
+    def num_tokens(self, index):
+        return self.item_size
+
+    def size(self, index):
+        return self.item_size
+
+    def ordered_indices(self):
+        return np.arange(self.num_items)
+
+    @property
+    def supports_prefetch(self):
+        return False

fairseq/benchmark/dummy_masked_lm.py

@@ -0,0 +1,127 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import logging
+
+import numpy as np
+import torch
+from fairseq.data import Dictionary, FairseqDataset
+from fairseq.tasks import LegacyFairseqTask, register_task
+
+
+logger = logging.getLogger(__name__)
+
+
+@register_task("dummy_masked_lm")
+class DummyMaskedLMTask(LegacyFairseqTask):
+    @staticmethod
+    def add_args(parser):
+        """Add task-specific arguments to the parser."""
+        parser.add_argument("--dict-size", default=49995, type=int)
+        parser.add_argument("--dataset-size", default=100000, type=int)
+        parser.add_argument(
+            "--tokens-per-sample",
+            default=512,
+            type=int,
+            help="max number of total tokens over all segments "
+            "per sample for BERT dataset",
+        )
+
+    def __init__(self, args, dictionary):
+        super().__init__(args)
+        self.dictionary = dictionary
+
+        # add mask token
+        self.mask_idx = dictionary.add_symbol("<mask>")
+        dictionary.pad_to_multiple_(8)  # often faster if divisible by 8
+
+        mask_idx = 0
+        pad_idx = 1
+        seq = torch.arange(args.tokens_per_sample) + pad_idx + 1
+        mask = torch.arange(2, args.tokens_per_sample, 7)  # ~15%
+        src = seq.clone()
+        src[mask] = mask_idx
+        tgt = torch.full_like(seq, pad_idx)
+        tgt[mask] = seq[mask]
+
+        self.dummy_src = src
+        self.dummy_tgt = tgt
+
+    @classmethod
+    def setup_task(cls, args, **kwargs):
+        """Setup the task. """
+        dictionary = Dictionary()
+        for i in range(args.dict_size):
+            dictionary.add_symbol("word{}".format(i))
+        logger.info("dictionary: {} types".format(len(dictionary)))
+        return cls(args, dictionary)
+
+    def load_dataset(self, split, epoch=1, combine=False, **kwargs):
+        """Load a given dataset split.
+        Args:
+            split (str): name of the split (e.g., train, valid, test)
+        """
+        if self.args.batch_size is not None:
+            bsz = self.args.batch_size
+        else:
+            bsz = max(1, self.args.max_tokens // self.args.tokens_per_sample)
+        self.datasets[split] = DummyDataset(
+            {
+                "id": 1,
+                "net_input": {
+                    "src_tokens": torch.stack([self.dummy_src for _ in range(bsz)]),
+                    "src_lengths": torch.full(
+                        (bsz,), self.args.tokens_per_sample, dtype=torch.long
+                    ),
+                },
+                "target": torch.stack([self.dummy_tgt for _ in range(bsz)]),
+                "nsentences": bsz,
+                "ntokens": bsz * self.args.tokens_per_sample,
+            },
+            num_items=self.args.dataset_size,
+            item_size=self.args.tokens_per_sample,
+        )
+
+    @property
+    def source_dictionary(self):
+        return self.dictionary
+
+    @property
+    def target_dictionary(self):
+        return self.dictionary
+
+
+class DummyDataset(FairseqDataset):
+    def __init__(self, batch, num_items, item_size):
+        super().__init__()
+        self.batch = batch
+        self.num_items = num_items
+        self.item_size = item_size
+
+    def __getitem__(self, index):
+        return index
+
+    def __len__(self):
+        return self.num_items
+
+    def collater(self, samples):
+        return self.batch
+
+    @property
+    def sizes(self):
+        return np.array([self.item_size] * self.num_items)
+
+    def num_tokens(self, index):
+        return self.item_size
+
+    def size(self, index):
+        return self.item_size
+
+    def ordered_indices(self):
+        return np.arange(self.num_items)
+
+    @property
+    def supports_prefetch(self):
+        return False

fairseq/benchmark/dummy_model.py

@@ -0,0 +1,96 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import torch.nn as nn
+import torch.nn.functional as F
+from fairseq.data import Dictionary
+from fairseq.models import (
+    FairseqDecoder,
+    FairseqLanguageModel,
+    register_model,
+    register_model_architecture,
+)
+
+
+@register_model("dummy_model")
+class DummyModel(FairseqLanguageModel):
+    def __init__(self, args, encoder):
+        super().__init__(encoder)
+        self.args = args
+
+    @staticmethod
+    def add_args(parser):
+        parser.add_argument("--num-layers", type=int, default=24)
+        parser.add_argument("--embed-dim", type=int, default=1024)
+
+    @classmethod
+    def build_model(cls, args, task):
+        encoder = DummyEncoder(
+            num_embed=len(task.target_dictionary),
+            embed_dim=args.embed_dim,
+            num_layers=args.num_layers,
+        )
+        return cls(args, encoder)
+
+    def forward(self, src_tokens, masked_tokens=None, **kwargs):
+        return self.decoder(src_tokens, masked_tokens=masked_tokens)
+
+
+class DummyEncoder(FairseqDecoder):
+    def __init__(self, num_embed=50000, embed_dim=1024, num_layers=24):
+        super().__init__(Dictionary())
+        self.embed = nn.Embedding(
+            num_embeddings=num_embed, embedding_dim=embed_dim, padding_idx=0
+        )
+        self.layers_a = nn.ModuleList(
+            [
+                nn.Sequential(
+                    nn.LayerNorm(embed_dim),
+                    nn.Linear(embed_dim, 3 * embed_dim),  # q, k, v input projection
+                    nn.Linear(3 * embed_dim, embed_dim),  # skip self-attention
+                    nn.Linear(embed_dim, embed_dim),  # output projection
+                    nn.Dropout(),
+                )
+                for i in range(num_layers)
+            ]
+        )
+        self.layers_b = nn.ModuleList(
+            [
+                nn.Sequential(
+                    nn.LayerNorm(embed_dim),
+                    nn.Linear(embed_dim, 4 * embed_dim),  # FFN
+                    nn.ReLU(),
+                    nn.Linear(4 * embed_dim, embed_dim),  # FFN
+                    nn.Dropout(0.1),
+                )
+                for i in range(num_layers)
+            ]
+        )
+        self.out_proj = nn.Linear(embed_dim, num_embed)
+
+    def forward(self, tokens, masked_tokens=None):
+        x = self.embed(tokens)
+        for layer_a, layer_b in zip(self.layers_a, self.layers_b):
+            x = x + layer_a(x)
+            x = x + layer_b(x)
+        x = self.out_proj(x)
+        if masked_tokens is not None:
+            x = x[masked_tokens]
+        return (x,)
+
+    def max_positions(self):
+        return 1024
+
+    def get_normalized_probs(self, net_output, log_probs, sample=None):
+        logits = net_output[0].float()
+        if log_probs:
+            return F.log_softmax(logits, dim=-1)
+        else:
+            return F.softmax(logits, dim=-1)
+
+
+@register_model_architecture("dummy_model", "dummy_model")
+def base_architecture(args):
+    pass

fairseq/benchmark/dummy_mt.py

@@ -0,0 +1,119 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import logging
+
+import numpy as np
+import torch
+from fairseq.data import Dictionary, FairseqDataset
+from fairseq.tasks import LegacyFairseqTask, register_task
+
+
+logger = logging.getLogger(__name__)
+
+
+@register_task("dummy_mt")
+class DummyMTTask(LegacyFairseqTask):
+    @staticmethod
+    def add_args(parser):
+        """Add task-specific arguments to the parser."""
+        parser.add_argument("--dict-size", default=49996, type=int)
+        parser.add_argument("--dataset-size", default=100000, type=int)
+        parser.add_argument("--src-len", default=30, type=int)
+        parser.add_argument("--tgt-len", default=30, type=int)
+
+    def __init__(self, args, dictionary):
+        super().__init__(args)
+        self.dictionary = dictionary
+        self.seed = args.seed
+
+        dictionary.pad_to_multiple_(8)  # often faster if divisible by 8
+
+        self.dummy_src = torch.arange(args.src_len + 1) + dictionary.pad() + 1
+        self.dummy_tgt = torch.arange(args.tgt_len + 1) + dictionary.pad() + 1
+
+    @classmethod
+    def setup_task(cls, args, **kwargs):
+        """Setup the task. """
+        dictionary = Dictionary()
+        for i in range(args.dict_size):
+            dictionary.add_symbol("word{}".format(i))
+        logger.info("dictionary: {} types".format(len(dictionary)))
+
+        args.max_source_positions = args.src_len + dictionary.pad() + 2
+        args.max_target_positions = args.tgt_len + dictionary.pad() + 2
+
+        return cls(args, dictionary)
+
+    def load_dataset(self, split, epoch=1, combine=False, **kwargs):
+        """Load a given dataset split.
+        Args:
+            split (str): name of the split (e.g., train, valid, test)
+        """
+        item_size = max(self.args.src_len, self.args.tgt_len)
+        if self.args.batch_size is not None:
+            bsz = self.args.batch_size
+        else:
+            bsz = max(1, self.args.max_tokens // item_size)
+        tgt = torch.stack([self.dummy_tgt for _ in range(bsz)])
+        self.datasets[split] = DummyDataset(
+            {
+                "id": 1,
+                "net_input": {
+                    "src_tokens": torch.stack([self.dummy_src for _ in range(bsz)]),
+                    "src_lengths": torch.full(
+                        (bsz,), self.args.src_len, dtype=torch.long
+                    ),
+                    "prev_output_tokens": tgt.clone(),
+                },
+                "target": tgt,
+                "nsentences": bsz,
+                "ntokens": bsz * self.args.tgt_len,
+            },
+            num_items=self.args.dataset_size,
+            item_size=item_size,
+        )
+
+    @property
+    def source_dictionary(self):
+        return self.dictionary
+
+    @property
+    def target_dictionary(self):
+        return self.dictionary
+
+
+class DummyDataset(FairseqDataset):
+    def __init__(self, batch, num_items, item_size):
+        super().__init__()
+        self.batch = batch
+        self.num_items = num_items
+        self.item_size = item_size
+
+    def __getitem__(self, index):
+        return index
+
+    def __len__(self):
+        return self.num_items
+
+    def collater(self, samples):
+        return self.batch
+
+    @property
+    def sizes(self):
+        return np.array([self.item_size] * self.num_items)
+
+    def num_tokens(self, index):
+        return self.item_size
+
+    def size(self, index):
+        return self.item_size
+
+    def ordered_indices(self):
+        return np.arange(self.num_items)
+
+    @property
+    def supports_prefetch(self):
+        return False

fairseq/binarizer.py

@@ -0,0 +1,105 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import os
+from collections import Counter
+
+import torch
+from fairseq.file_io import PathManager
+from fairseq.tokenizer import tokenize_line
+
+
+def safe_readline(f):
+    pos = f.tell()
+    while True:
+        try:
+            return f.readline()
+        except UnicodeDecodeError:
+            pos -= 1
+            f.seek(pos)  # search where this character begins
+
+
+class Binarizer:
+    @staticmethod
+    def binarize(
+        filename,
+        dict,
+        consumer,
+        tokenize=tokenize_line,
+        append_eos=True,
+        reverse_order=False,
+        offset=0,
+        end=-1,
+        already_numberized=False,
+    ):
+        nseq, ntok = 0, 0
+        replaced = Counter()
+
+        def replaced_consumer(word, idx):
+            if idx == dict.unk_index and word != dict.unk_word:
+                replaced.update([word])
+
+        with open(PathManager.get_local_path(filename), "r", encoding="utf-8") as f:
+            f.seek(offset)
+            # next(f) breaks f.tell(), hence readline() must be used
+            line = safe_readline(f)
+            while line:
+                if end > 0 and f.tell() > end:
+                    break
+                if already_numberized:
+                    id_strings = line.strip().split()
+                    id_list = [int(id_string) for id_string in id_strings]
+                    if reverse_order:
+                        id_list.reverse()
+                    if append_eos:
+                        id_list.append(dict.eos())
+                    ids = torch.IntTensor(id_list)
+                else:
+                    ids = dict.encode_line(
+                        line=line,
+                        line_tokenizer=tokenize,
+                        add_if_not_exist=False,
+                        consumer=replaced_consumer,
+                        append_eos=append_eos,
+                        reverse_order=reverse_order,
+                    )
+                nseq += 1
+                ntok += len(ids)
+                consumer(ids)
+                line = f.readline()
+        return {
+            "nseq": nseq,
+            "nunk": sum(replaced.values()),
+            "ntok": ntok,
+            "replaced": replaced,
+        }
+
+    @staticmethod
+    def binarize_alignments(filename, alignment_parser, consumer, offset=0, end=-1):
+        nseq = 0
+
+        with open(PathManager.get_local_path(filename), "r") as f:
+            f.seek(offset)
+            line = safe_readline(f)
+            while line:
+                if end > 0 and f.tell() > end:
+                    break
+                ids = alignment_parser(line)
+                nseq += 1
+                consumer(ids)
+                line = f.readline()
+        return {"nseq": nseq}
+
+    @staticmethod
+    def find_offsets(filename, num_chunks):
+        with open(PathManager.get_local_path(filename), "r", encoding="utf-8") as f:
+            size = os.fstat(f.fileno()).st_size
+            chunk_size = size // num_chunks
+            offsets = [0 for _ in range(num_chunks + 1)]
+            for i in range(1, num_chunks):
+                f.seek(chunk_size * i)
+                safe_readline(f)
+                offsets[i] = f.tell()
+            return offsets

fairseq/checkpoint_utils.py

@@ -0,0 +1,610 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import ast
+import collections
+import logging
+import os
+import re
+import traceback
+from collections import OrderedDict
+from typing import Optional, Union
+
+import torch
+from fairseq.dataclass.configs import CheckpointConfig, FairseqConfig
+from fairseq.dataclass.utils import (
+    convert_namespace_to_omegaconf,
+    overwrite_args_by_name,
+)
+from fairseq.file_io import PathManager
+from fairseq.models import FairseqDecoder, FairseqEncoder
+from omegaconf import DictConfig, open_dict
+from torch.serialization import default_restore_location
+
+
+logger = logging.getLogger(__name__)
+
+
+def save_checkpoint(cfg: CheckpointConfig, trainer, epoch_itr, val_loss):
+    from fairseq import meters
+
+    # only one worker should attempt to create the required dir
+    if cfg.distributed_rank == 0:
+        os.makedirs(cfg.save_dir, exist_ok=True)
+
+    prev_best = getattr(save_checkpoint, "best", val_loss)
+    if val_loss is not None:
+        best_function = max if cfg.maximize_best_checkpoint_metric else min
+        save_checkpoint.best = best_function(val_loss, prev_best)
+
+    if cfg.no_save:
+        return
+
+    trainer.consolidate_optimizer()
+
+    if not trainer.is_data_parallel_master:
+        return
+
+    def is_better(a, b):
+        return a >= b if cfg.maximize_best_checkpoint_metric else a <= b
+
+    write_timer = meters.StopwatchMeter()
+    write_timer.start()
+
+    epoch = epoch_itr.epoch
+    end_of_epoch = epoch_itr.end_of_epoch()
+    updates = trainer.get_num_updates()
+
+    suffix = cfg.checkpoint_suffix or ""
+    checkpoint_conds = collections.OrderedDict()
+    checkpoint_conds["checkpoint{}{}.pt".format(epoch, suffix)] = (
+        end_of_epoch and not cfg.no_epoch_checkpoints and epoch % cfg.save_interval == 0
+    )
+    checkpoint_conds["checkpoint_{}_{}{}.pt".format(epoch, updates, suffix)] = (
+        not end_of_epoch
+        and cfg.save_interval_updates > 0
+        and updates % cfg.save_interval_updates == 0
+    )
+    checkpoint_conds["checkpoint_best{}.pt".format(suffix)] = val_loss is not None and (
+        not hasattr(save_checkpoint, "best")
+        or is_better(val_loss, save_checkpoint.best)
+    )
+    if val_loss is not None and cfg.keep_best_checkpoints > 0:
+        checkpoint_conds[
+            "checkpoint.best_{}_{:.2f}.pt".format(cfg.best_checkpoint_metric, val_loss)
+        ] = not hasattr(save_checkpoint, "best") or is_better(
+            val_loss, save_checkpoint.best
+        )
+    checkpoint_conds[
+        "checkpoint_last{}.pt".format(suffix)
+    ] = not cfg.no_last_checkpoints
+
+    extra_state = {"train_iterator": epoch_itr.state_dict(), "val_loss": val_loss}
+    if hasattr(save_checkpoint, "best"):
+        extra_state.update({"best": save_checkpoint.best})
+
+    checkpoints = [
+        os.path.join(cfg.save_dir, fn) for fn, cond in checkpoint_conds.items() if cond
+    ]
+    if len(checkpoints) > 0:
+        trainer.save_checkpoint(checkpoints[0], extra_state)
+        for cp in checkpoints[1:]:
+            PathManager.copy(checkpoints[0], cp, overwrite=True)
+
+        write_timer.stop()
+        logger.info(
+            "saved checkpoint {} (epoch {} @ {} updates, score {}) (writing took {} seconds)".format(
+                checkpoints[0], epoch, updates, val_loss, write_timer.sum
+            )
+        )
+
+    if not end_of_epoch and cfg.keep_interval_updates > 0:
+        # remove old checkpoints; checkpoints are sorted in descending order
+        checkpoints = checkpoint_paths(
+            cfg.save_dir, pattern=r"checkpoint_\d+_(\d+)\.pt"
+        )
+        for old_chk in checkpoints[cfg.keep_interval_updates :]:
+            if os.path.lexists(old_chk):
+                os.remove(old_chk)
+
+    if cfg.keep_last_epochs > 0:
+        # remove old epoch checkpoints; checkpoints are sorted in descending order
+        checkpoints = checkpoint_paths(cfg.save_dir, pattern=r"checkpoint(\d+)\.pt")
+        for old_chk in checkpoints[cfg.keep_last_epochs :]:
+            if os.path.lexists(old_chk):
+                os.remove(old_chk)
+
+    if cfg.keep_best_checkpoints > 0:
+        # only keep the best N checkpoints according to validation metric
+        checkpoints = checkpoint_paths(
+            cfg.save_dir,
+            pattern=r"checkpoint\.best_{}_(\d+\.?\d*)\.pt".format(
+                cfg.best_checkpoint_metric
+            ),
+        )
+        if not cfg.maximize_best_checkpoint_metric:
+            checkpoints = checkpoints[::-1]
+        for old_chk in checkpoints[cfg.keep_best_checkpoints :]:
+            if os.path.lexists(old_chk):
+                os.remove(old_chk)
+
+
+def load_checkpoint(cfg: CheckpointConfig, trainer, **passthrough_args):
+    """
+    Load a checkpoint and restore the training iterator.
+
+    *passthrough_args* will be passed through to
+    ``trainer.get_train_iterator``.
+    """
+
+    reset_optimizer = cfg.reset_optimizer
+    reset_lr_scheduler = cfg.reset_lr_scheduler
+    optimizer_overrides = ast.literal_eval(cfg.optimizer_overrides)
+    reset_meters = cfg.reset_meters
+    reset_dataloader = cfg.reset_dataloader
+
+    if cfg.finetune_from_model is not None and (
+        reset_optimizer or reset_lr_scheduler or reset_meters or reset_dataloader
+    ):
+        raise ValueError(
+            "--finetune-from-model can not be set together with either --reset-optimizer"
+            " or reset_lr_scheduler or reset_meters or reset_dataloader"
+        )
+
+    suffix = cfg.checkpoint_suffix
+    if (
+        cfg.restore_file == "checkpoint_last.pt"
+    ):  # default value of restore_file is 'checkpoint_last.pt'
+        checkpoint_path = os.path.join(
+            cfg.save_dir, "checkpoint_last{}.pt".format(suffix)
+        )
+        first_launch = not PathManager.exists(checkpoint_path)
+        if cfg.finetune_from_model is not None and first_launch:
+            # if there is no last checkpoint to restore, start the finetune from pretrained model
+            # else just use usual logic to load checkpoint, e.g. restart from last checkpoint and etc.
+            if PathManager.exists(cfg.finetune_from_model):
+                checkpoint_path = cfg.finetune_from_model
+                reset_optimizer = True
+                reset_lr_scheduler = True
+                reset_meters = True
+                reset_dataloader = True
+                logger.info(
+                    f"loading pretrained model from {checkpoint_path}: "
+                    "optimizer, lr scheduler, meters, dataloader will be reset"
+                )
+            else:
+                raise ValueError(
+                    f"--funetune-from-model {cfg.finetune_from_model} does not exist"
+                )
+    elif cfg.model_parallel_size > 1:
+        checkpoint_path = cfg.restore_file.replace(".pt", suffix + ".pt")
+    else:
+        checkpoint_path = cfg.restore_file
+
+    if cfg.restore_file != "checkpoint_last.pt" and cfg.finetune_from_model:
+        raise ValueError(
+            "--finetune-from-model and --restore-file (non-default value) "
+            "can not be specified together: " + str(cfg)
+        )
+
+    extra_state = trainer.load_checkpoint(
+        checkpoint_path,
+        reset_optimizer,
+        reset_lr_scheduler,
+        optimizer_overrides,
+        reset_meters=reset_meters,
+    )
+
+    if (
+        extra_state is not None
+        and "best" in extra_state
+        and not reset_optimizer
+        and not reset_meters
+    ):
+        save_checkpoint.best = extra_state["best"]
+
+    if extra_state is not None and not reset_dataloader:
+        # restore iterator from checkpoint
+        itr_state = extra_state["train_iterator"]
+        epoch_itr = trainer.get_train_iterator(
+            epoch=itr_state["epoch"], load_dataset=True, **passthrough_args
+        )
+        epoch_itr.load_state_dict(itr_state)
+    else:
+        epoch_itr = trainer.get_train_iterator(
+            epoch=1, load_dataset=True, **passthrough_args
+        )
+
+    trainer.lr_step(epoch_itr.epoch)
+
+    return extra_state, epoch_itr
+
+
+def load_checkpoint_to_cpu(path, arg_overrides=None):
+    """Loads a checkpoint to CPU (with upgrading for backward compatibility)."""
+    with open(PathManager.get_local_path(path), "rb") as f:
+        state = torch.load(
+            f, map_location=lambda s, l: default_restore_location(s, "cpu")
+        )
+
+    if "args" in state and state["args"] is not None and arg_overrides is not None:
+        args = state["args"]
+        for arg_name, arg_val in arg_overrides.items():
+            setattr(args, arg_name, arg_val)
+
+    if "cfg" in state and state["cfg"] is not None and arg_overrides is not None:
+        overwrite_args_by_name(state["cfg"], arg_overrides)
+
+    state = _upgrade_state_dict(state)
+    return state
+
+
+def load_model_ensemble(
+    filenames, arg_overrides=None, task=None, strict=True, suffix="", num_shards=1
+):
+    """Loads an ensemble of models.
+
+    Args:
+        filenames (List[str]): checkpoint files to load
+        arg_overrides (Dict[str,Any], optional): override model args that
+            were used during model training
+        task (fairseq.tasks.FairseqTask, optional): task to use for loading
+    """
+    assert not (
+        strict and num_shards > 1
+    ), "Cannot load state dict with strict=True and checkpoint shards > 1"
+    ensemble, args, _task = load_model_ensemble_and_task(
+        filenames,
+        arg_overrides,
+        task,
+        strict,
+        suffix,
+        num_shards,
+    )
+    return ensemble, args
+
+
+def load_model_ensemble_and_task(
+    filenames, arg_overrides=None, task=None, strict=True, suffix="", num_shards=1
+):
+    from fairseq import tasks
+
+    assert not (
+        strict and num_shards > 1
+    ), "Cannot load state dict with strict=True and checkpoint shards > 1"
+    ensemble = []
+    for filename in filenames:
+        orig_filename = filename
+        for shard_idx in range(num_shards):
+            if num_shards == 1:
+                filename = filename.replace(".pt", suffix + ".pt")
+            else:
+                filename = orig_filename[:-3] + f"_part{shard_idx}.pt"
+
+            if not PathManager.exists(filename):
+                raise IOError("Model file not found: {}".format(filename))
+            state = load_checkpoint_to_cpu(filename, arg_overrides)
+            if "args" in state and state["args"] is not None:
+                cfg = convert_namespace_to_omegaconf(state["args"])
+            elif "cfg" in state and state["cfg"] is not None:
+                cfg = state["cfg"]
+            else:
+                raise RuntimeError(
+                    f"Neither args nor cfg exist in state keys = {state.keys()}"
+                )
+
+            if task is None:
+                task = tasks.setup_task(cfg.task)
+
+            # build model for ensemble
+            model = task.build_model(cfg.model)
+
+            model.load_state_dict(state["model"], strict=strict, model_cfg=cfg.model)
+        ensemble.append(model)
+    return ensemble, cfg, task
+
+
+def checkpoint_paths(path, pattern=r"checkpoint(\d+)\.pt"):
+    """Retrieves all checkpoints found in `path` directory.
+
+    Checkpoints are identified by matching filename to the specified pattern. If
+    the pattern contains groups, the result will be sorted by the first group in
+    descending order.
+    """
+    pt_regexp = re.compile(pattern)
+    files = os.listdir(path)
+
+    entries = []
+    for i, f in enumerate(files):
+        m = pt_regexp.fullmatch(f)
+        if m is not None:
+            idx = float(m.group(1)) if len(m.groups()) > 0 else i
+            entries.append((idx, m.group(0)))
+    return [os.path.join(path, x[1]) for x in sorted(entries, reverse=True)]
+
+
+def torch_persistent_save(obj, f):
+    if isinstance(f, str):
+        with PathManager.open(f, "wb") as h:
+            torch_persistent_save(obj, h)
+        return
+    for i in range(3):
+        try:
+            return torch.save(obj, f)
+        except Exception:
+            if i == 2:
+                logger.error(traceback.format_exc())
+
+
+def save_state(
+    filename,
+    cfg: FairseqConfig,
+    model_state_dict,
+    criterion,
+    optimizer,
+    lr_scheduler,
+    num_updates,
+    optim_history=None,
+    extra_state=None,
+    **kwargs,
+):
+    from fairseq import utils
+
+    if optim_history is None:
+        optim_history = []
+    if extra_state is None:
+        extra_state = {}
+    state_dict = {
+        "cfg": cfg,
+        "args": kwargs.get("args", None),
+        "model": model_state_dict or {},
+        "optimizer_history": optim_history
+        + [
+            {
+                "criterion_name": criterion.__class__.__name__,
+                "optimizer_name": optimizer.__class__.__name__,
+                "lr_scheduler_state": lr_scheduler.state_dict(),
+                "num_updates": num_updates,
+            }
+        ],
+        "extra_state": extra_state,
+    }
+    if utils.has_parameters(criterion):
+        state_dict["criterion"] = criterion.state_dict()
+
+    if cfg is None:
+        cfg = state_dict["args"]
+        assert cfg is not None, "must provide cfg or args"
+
+    if isinstance(cfg, DictConfig):
+        no_save_optimizer_state = cfg.checkpoint.no_save_optimizer_state
+    else:
+        no_save_optimizer_state = cfg.no_save_optimizer_state
+    if not no_save_optimizer_state:
+        state_dict["last_optimizer_state"] = optimizer.state_dict()
+
+    with PathManager.open(filename, "wb") as f:
+        torch_persistent_save(state_dict, f)
+
+
+def _upgrade_state_dict(state):
+    """Helper for upgrading old model checkpoints."""
+    from fairseq import models, registry, tasks
+
+    # add optimizer_history
+    if "optimizer_history" not in state:
+        state["optimizer_history"] = [
+            {"criterion_name": "CrossEntropyCriterion", "best_loss": state["best_loss"]}
+        ]
+        state["last_optimizer_state"] = state["optimizer"]
+        del state["optimizer"]
+        del state["best_loss"]
+    # move extra_state into sub-dictionary
+    if "epoch" in state and "extra_state" not in state:
+        state["extra_state"] = {
+            "epoch": state["epoch"],
+            "batch_offset": state["batch_offset"],
+            "val_loss": state["val_loss"],
+        }
+        del state["epoch"]
+        del state["batch_offset"]
+        del state["val_loss"]
+    # reduce optimizer history's memory usage (only keep the last state)
+    if "optimizer" in state["optimizer_history"][-1]:
+        state["last_optimizer_state"] = state["optimizer_history"][-1]["optimizer"]
+        for optim_hist in state["optimizer_history"]:
+            del optim_hist["optimizer"]
+    # record the optimizer class name
+    if "optimizer_name" not in state["optimizer_history"][-1]:
+        state["optimizer_history"][-1]["optimizer_name"] = "FairseqNAG"
+    # move best_loss into lr_scheduler_state
+    if "lr_scheduler_state" not in state["optimizer_history"][-1]:
+        state["optimizer_history"][-1]["lr_scheduler_state"] = {
+            "best": state["optimizer_history"][-1]["best_loss"]
+        }
+        del state["optimizer_history"][-1]["best_loss"]
+    # keep track of number of updates
+    if "num_updates" not in state["optimizer_history"][-1]:
+        state["optimizer_history"][-1]["num_updates"] = 0
+    # use stateful training data iterator
+    if "train_iterator" not in state["extra_state"]:
+        state["extra_state"]["train_iterator"] = {
+            "epoch": state["extra_state"]["epoch"],
+            "iterations_in_epoch": state["extra_state"].get("batch_offset", 0),
+        }
+
+    # old model checkpoints may not have separate source/target positions
+    # backward compatibility, cfg updates
+    if "args" in state and state["args"] is not None:
+        # default to translation task
+        if not hasattr(state["args"], "task"):
+            state["args"].task = "translation"
+        # --raw-text and --lazy-load are deprecated
+        if getattr(state["args"], "raw_text", False):
+            state["args"].dataset_impl = "raw"
+        elif getattr(state["args"], "lazy_load", False):
+            state["args"].dataset_impl = "lazy"
+        # epochs start at 1
+        if state["extra_state"]["train_iterator"] is not None:
+            state["extra_state"]["train_iterator"]["epoch"] = max(
+                state["extra_state"]["train_iterator"].get("epoch", 1), 1
+            )
+
+        if hasattr(state["args"], "remove_bpe"):
+            state["args"].post_process = state["args"].remove_bpe
+
+        state["cfg"] = convert_namespace_to_omegaconf(state["args"])
+
+    if "cfg" in state and state["cfg"] is not None:
+        with open_dict(state["cfg"]):
+            if state["cfg"].task is not None:
+                if hasattr(state["cfg"].task, "max_positions") and not hasattr(
+                    state["cfg"].task, "max_source_positions"
+                ):
+                    state["cfg"].task.max_source_positions = state[
+                        "cfg"
+                    ].task.max_positions
+                    state["cfg"].task.max_target_positions = state[
+                        "cfg"
+                    ].task.max_positions
+
+    return state
+
+
+def prune_state_dict(state_dict, model_cfg: Optional[DictConfig]):
+    """Prune the given state_dict if desired for LayerDrop
+    (https://arxiv.org/abs/1909.11556).
+
+    Training with LayerDrop allows models to be robust to pruning at inference
+    time. This function prunes state_dict to allow smaller models to be loaded
+    from a larger model and re-maps the existing state_dict for this to occur.
+
+    It's called by functions that load models from checkpoints and does not
+    need to be called directly.
+    """
+    arch = None
+    if model_cfg is not None:
+        arch = (
+            model_cfg._name
+            if isinstance(model_cfg, DictConfig)
+            else getattr(model_cfg, "arch", None)
+        )
+
+    if not model_cfg or arch is None or arch == "ptt_transformer":
+        # args should not be none, but don't crash if it is.
+        return state_dict
+
+    encoder_layers_to_keep = getattr(model_cfg, "encoder_layers_to_keep", None)
+    decoder_layers_to_keep = getattr(model_cfg, "decoder_layers_to_keep", None)
+
+    if not encoder_layers_to_keep and not decoder_layers_to_keep:
+        return state_dict
+
+    # apply pruning
+    logger.info(
+        "Pruning model to specified layer configuration - this works best if the model was trained with LayerDrop"
+    )
+
+    def create_pruning_pass(layers_to_keep, layer_name):
+        keep_layers = sorted(
+            int(layer_string) for layer_string in layers_to_keep.split(",")
+        )
+        mapping_dict = {}
+        for i in range(len(keep_layers)):
+            mapping_dict[str(keep_layers[i])] = str(i)
+
+        regex = re.compile(r"^{layer}.*\.layers\.(\d+)".format(layer=layer_name))
+        return {"substitution_regex": regex, "mapping_dict": mapping_dict}
+
+    pruning_passes = []
+    if encoder_layers_to_keep:
+        pruning_passes.append(create_pruning_pass(encoder_layers_to_keep, "encoder"))
+    if decoder_layers_to_keep:
+        pruning_passes.append(create_pruning_pass(decoder_layers_to_keep, "decoder"))
+
+    new_state_dict = {}
+    for layer_name in state_dict.keys():
+        match = re.search(r"\.layers\.(\d+)\.", layer_name)
+        # if layer has no number in it, it is a supporting layer, such as an
+        # embedding
+        if not match:
+            new_state_dict[layer_name] = state_dict[layer_name]
+            continue
+
+        # otherwise, layer should be pruned.
+        original_layer_number = match.group(1)
+        # figure out which mapping dict to replace from
+        for pruning_pass in pruning_passes:
+            if original_layer_number in pruning_pass["mapping_dict"] and pruning_pass[
+                "substitution_regex"
+            ].search(layer_name):
+                new_layer_number = pruning_pass["mapping_dict"][original_layer_number]
+                substitution_match = pruning_pass["substitution_regex"].search(
+                    layer_name
+                )
+                new_state_key = (
+                    layer_name[: substitution_match.start(1)]
+                    + new_layer_number
+                    + layer_name[substitution_match.end(1) :]
+                )
+                new_state_dict[new_state_key] = state_dict[layer_name]
+
+    # Since layers are now pruned, *_layers_to_keep are no longer needed.
+    # This is more of "It would make it work fix" rather than a proper fix.
+
+    with open_dict(model_cfg):
+        if hasattr(model_cfg, "encoder_layers_to_keep"):
+            model_cfg.encoder_layers_to_keep = None
+        if hasattr(model_cfg, "decoder_layers_to_keep"):
+            model_cfg.decoder_layers_to_keep = None
+
+    return new_state_dict
+
+
+def load_pretrained_component_from_model(
+    component: Union[FairseqEncoder, FairseqDecoder], checkpoint: str
+):
+    """
+    Load a pretrained FairseqEncoder or FairseqDecoder from checkpoint into the
+    provided `component` object. If state_dict fails to load, there may be a
+    mismatch in the architecture of the corresponding `component` found in the
+    `checkpoint` file.
+    """
+    if not PathManager.exists(checkpoint):
+        raise IOError("Model file not found: {}".format(checkpoint))
+    state = load_checkpoint_to_cpu(checkpoint)
+    if isinstance(component, FairseqEncoder):
+        component_type = "encoder"
+    elif isinstance(component, FairseqDecoder):
+        component_type = "decoder"
+    else:
+        raise ValueError(
+            "component to load must be either a FairseqEncoder or "
+            "FairseqDecoder. Loading other component types are not supported."
+        )
+    component_state_dict = OrderedDict()
+    for key in state["model"].keys():
+        if key.startswith(component_type):
+            # encoder.input_layers.0.0.weight --> input_layers.0.0.weight
+            component_subkey = key[len(component_type) + 1 :]
+            component_state_dict[component_subkey] = state["model"][key]
+    component.load_state_dict(component_state_dict, strict=True)
+    return component
+
+
+def verify_checkpoint_directory(save_dir: str) -> None:
+    if not os.path.exists(save_dir):
+        os.makedirs(save_dir, exist_ok=True)
+    temp_file_path = os.path.join(save_dir, "dummy")
+    try:
+        with open(temp_file_path, "w"):
+            pass
+    except OSError as e:
+        logger.warning(
+            "Unable to access checkpoint save directory: {}".format(save_dir)
+        )
+        raise e
+    else:
+        os.remove(temp_file_path)

fairseq/clib/libbleu/libbleu.cpp

@@ -0,0 +1,141 @@
+/**
+ * Copyright 2017-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <map>
+#include <array>
+#include <cstring>
+#include <cstdio>
+
+typedef struct
+{
+    size_t reflen;
+    size_t predlen;
+    size_t match1;
+    size_t count1;
+    size_t match2;
+    size_t count2;
+    size_t match3;
+    size_t count3;
+    size_t match4;
+    size_t count4;
+} bleu_stat;
+
+// left trim (remove pad)
+void bleu_ltrim(size_t* len, int** sent, int pad) {
+  size_t start = 0;
+  while(start < *len) {
+    if (*(*sent + start) != pad) { break; }
+    start++;
+  }
+  *sent += start;
+  *len -= start;
+}
+
+// right trim remove (eos)
+void bleu_rtrim(size_t* len, int** sent, int pad, int eos) {
+  size_t end = *len - 1;
+  while (end > 0) {
+    if (*(*sent + end) != eos && *(*sent + end) != pad) { break; }
+    end--;
+  }
+  *len = end + 1;
+}
+
+// left and right trim
+void bleu_trim(size_t* len, int** sent, int pad, int eos) {
+  bleu_ltrim(len, sent, pad);
+  bleu_rtrim(len, sent, pad, eos);
+}
+
+size_t bleu_hash(int len, int* data) {
+  size_t h     = 14695981039346656037ul;
+  size_t prime = 0x100000001b3;
+  char* b      = (char*) data;
+  size_t blen  = sizeof(int) * len;
+
+  while (blen-- > 0) {
+    h ^= *b++;
+    h *= prime;
+  }
+
+  return h;
+}
+
+void bleu_addngram(
+    size_t *ntotal, size_t *nmatch, size_t n,
+    size_t reflen, int* ref, size_t predlen, int* pred) {
+
+  if (predlen < n) { return; }
+
+  predlen = predlen - n + 1;
+  (*ntotal) += predlen;
+
+  if (reflen < n) { return; }
+
+  reflen = reflen - n + 1;
+
+  std::map<size_t, size_t> count;
+  while (predlen > 0) {
+    size_t w = bleu_hash(n, pred++);
+    count[w]++;
+    predlen--;
+  }
+
+  while (reflen > 0) {
+    size_t w = bleu_hash(n, ref++);
+    if (count[w] > 0) {
+      (*nmatch)++;
+      count[w] -=1;
+    }
+    reflen--;
+  }
+}
+
+extern "C" {
+
+#ifdef _WIN64
+__declspec(dllexport) 
+#endif
+void bleu_zero_init(bleu_stat* stat) {
+  std::memset(stat, 0, sizeof(bleu_stat));
+}
+
+#ifdef _WIN64
+__declspec(dllexport) 
+#endif
+void bleu_one_init(bleu_stat* stat) {
+  bleu_zero_init(stat);
+  stat->count1 = 0;
+  stat->count2 = 1;
+  stat->count3 = 1;
+  stat->count4 = 1;
+  stat->match1 = 0;
+  stat->match2 = 1;
+  stat->match3 = 1;
+  stat->match4 = 1;
+}
+
+#ifdef _WIN64
+__declspec(dllexport) 
+#endif
+void bleu_add(
+    bleu_stat* stat,
+    size_t reflen, int* ref, size_t predlen, int* pred, int pad, int eos) {
+
+  bleu_trim(&reflen, &ref, pad, eos);
+  bleu_trim(&predlen, &pred, pad, eos);
+  stat->reflen += reflen;
+  stat->predlen += predlen;
+
+  bleu_addngram(&stat->count1, &stat->match1, 1, reflen, ref, predlen, pred);
+  bleu_addngram(&stat->count2, &stat->match2, 2, reflen, ref, predlen, pred);
+  bleu_addngram(&stat->count3, &stat->match3, 3, reflen, ref, predlen, pred);
+  bleu_addngram(&stat->count4, &stat->match4, 4, reflen, ref, predlen, pred);
+}
+
+}

fairseq/clib/libbleu/module.cpp

@@ -0,0 +1,37 @@
+/**
+ * Copyright 2017-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <Python.h>
+
+
+static PyMethodDef method_def[] = {
+  {NULL, NULL, 0, NULL}
+};
+
+static struct PyModuleDef module_def = {
+   PyModuleDef_HEAD_INIT,
+   "libbleu",   /* name of module */
+   NULL,     /* module documentation, may be NULL */
+   -1,       /* size of per-interpreter state of the module,
+                or -1 if the module keeps state in global variables. */
+   method_def
+};
+
+
+#if PY_MAJOR_VERSION == 2
+PyMODINIT_FUNC init_libbleu()
+#else
+PyMODINIT_FUNC PyInit_libbleu()
+#endif
+{
+  PyObject *m = PyModule_Create(&module_def);
+  if (!m) {
+    return NULL;
+  }
+  return m;
+}

fairseq/clib/libnat/edit_dist.cpp

@@ -0,0 +1,231 @@
+/**
+ * Copyright 2017-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <torch/torch.h> // @manual=//caffe2:torch_extension
+#include <pybind11/detail/common.h>
+#include <pybind11/pybind11.h>
+#include <vector>
+#include <algorithm>
+#include <cstdint>
+#include <iosfwd>
+#include <memory>
+#include <new>
+#include <string>
+#include <utility>
+
+using namespace ::std;
+
+vector<vector<uint32_t>> edit_distance2_with_dp(
+    vector<uint32_t>& x,
+    vector<uint32_t>& y) {
+  uint32_t lx = x.size();
+  uint32_t ly = y.size();
+  vector<vector<uint32_t>> d(lx + 1, vector<uint32_t>(ly + 1));
+  for (uint32_t i = 0; i < lx + 1; i++) {
+    d[i][0] = i;
+  }
+  for (uint32_t j = 0; j < ly + 1; j++) {
+    d[0][j] = j;
+  }
+  for (uint32_t i = 1; i < lx + 1; i++) {
+    for (uint32_t j = 1; j < ly + 1; j++) {
+      d[i][j] =
+          min(min(d[i - 1][j], d[i][j - 1]) + 1,
+              d[i - 1][j - 1] + 2 * (x.at(i - 1) == y.at(j - 1) ? 0 : 1));
+    }
+  }
+  return d;
+}
+
+vector<vector<uint32_t>> edit_distance2_backtracking(
+    vector<vector<uint32_t>>& d,
+    vector<uint32_t>& x,
+    vector<uint32_t>& y,
+    uint32_t terminal_symbol) {
+  vector<uint32_t> seq;
+  vector<vector<uint32_t>> edit_seqs(x.size() + 2, vector<uint32_t>());
+  /*
+  edit_seqs:
+  0~x.size() cell is the insertion sequences
+  last cell is the delete sequence
+  */
+
+  if (x.size() == 0) {
+    edit_seqs.at(0) = y;
+    return edit_seqs;
+  }
+
+  uint32_t i = d.size() - 1;
+  uint32_t j = d.at(0).size() - 1;
+
+  while ((i >= 0) && (j >= 0)) {
+    if ((i == 0) && (j == 0)) {
+      break;
+    }
+
+    if ((j > 0) && (d.at(i).at(j - 1) < d.at(i).at(j))) {
+      seq.push_back(1); // insert
+      seq.push_back(y.at(j - 1));
+      j--;
+    } else if ((i > 0) && (d.at(i - 1).at(j) < d.at(i).at(j))) {
+      seq.push_back(2); // delete
+      seq.push_back(x.at(i - 1));
+      i--;
+    } else {
+      seq.push_back(3); // keep
+      seq.push_back(x.at(i - 1));
+      i--;
+      j--;
+    }
+  }
+
+  uint32_t prev_op, op, s, word;
+  prev_op = 0, s = 0;
+  for (uint32_t k = 0; k < seq.size() / 2; k++) {
+    op = seq.at(seq.size() - 2 * k - 2);
+    word = seq.at(seq.size() - 2 * k - 1);
+    if (prev_op != 1) {
+      s++;
+    }
+    if (op == 1) // insert
+    {
+      edit_seqs.at(s - 1).push_back(word);
+    } else if (op == 2) // delete
+    {
+      edit_seqs.at(x.size() + 1).push_back(1);
+    } else {
+      edit_seqs.at(x.size() + 1).push_back(0);
+    }
+
+    prev_op = op;
+  }
+
+  for (uint32_t k = 0; k < edit_seqs.size(); k++) {
+    if (edit_seqs[k].size() == 0) {
+      edit_seqs[k].push_back(terminal_symbol);
+    }
+  }
+  return edit_seqs;
+}
+
+vector<vector<uint32_t>> edit_distance2_backtracking_with_delete(
+    vector<vector<uint32_t>>& d,
+    vector<uint32_t>& x,
+    vector<uint32_t>& y,
+    uint32_t terminal_symbol,
+    uint32_t deletion_symbol) {
+  vector<uint32_t> seq;
+  vector<vector<uint32_t>> edit_seqs(x.size() + 1, vector<uint32_t>());
+  /*
+  edit_seqs:
+  0~x.size() cell is the insertion sequences
+  last cell is the delete sequence
+  */
+
+  if (x.size() == 0) {
+    edit_seqs.at(0) = y;
+    return edit_seqs;
+  }
+
+  uint32_t i = d.size() - 1;
+  uint32_t j = d.at(0).size() - 1;
+
+  while ((i >= 0) && (j >= 0)) {
+    if ((i == 0) && (j == 0)) {
+      break;
+    }
+
+    if ((j > 0) && (d.at(i).at(j - 1) < d.at(i).at(j))) {
+      seq.push_back(1); // insert
+      seq.push_back(y.at(j - 1));
+      j--;
+    } else if ((i > 0) && (d.at(i - 1).at(j) < d.at(i).at(j))) {
+      seq.push_back(2); // delete
+      seq.push_back(x.at(i - 1));
+      i--;
+    } else {
+      seq.push_back(3); // keep
+      seq.push_back(x.at(i - 1));
+      i--;
+      j--;
+    }
+  }
+
+  uint32_t prev_op, op, s, word;
+  prev_op = 0, s = 0;
+  for (uint32_t k = 0; k < seq.size() / 2; k++) {
+    op = seq.at(seq.size() - 2 * k - 2);
+    word = seq.at(seq.size() - 2 * k - 1);
+    if (prev_op != 1) {
+      s++;
+    }
+    if (op == 1) // insert
+    {
+      edit_seqs.at(s - 1).push_back(word);
+    } else if (op == 2) // delete
+    {
+      edit_seqs.at(s - 1).push_back(deletion_symbol);
+    }
+
+    prev_op = op;
+  }
+
+  for (uint32_t k = 0; k < edit_seqs.size(); k++) {
+    if (edit_seqs.at(k).size() == 0) {
+      edit_seqs.at(k).push_back(terminal_symbol);
+    }
+  }
+  return edit_seqs;
+}
+
+vector<uint32_t> compute_ed2(
+    vector<vector<uint32_t>>& xs,
+    vector<vector<uint32_t>>& ys) {
+  vector<uint32_t> distances(xs.size());
+  for (uint32_t i = 0; i < xs.size(); i++) {
+    vector<vector<uint32_t>> d = edit_distance2_with_dp(xs.at(i), ys.at(i));
+    distances.at(i) = d.at(xs.at(i).size()).at(ys.at(i).size());
+  }
+  return distances;
+}
+
+vector<vector<vector<uint32_t>>> suggested_ed2_path(
+    vector<vector<uint32_t>>& xs,
+    vector<vector<uint32_t>>& ys,
+    uint32_t terminal_symbol) {
+  vector<vector<vector<uint32_t>>> seq(xs.size());
+  for (uint32_t i = 0; i < xs.size(); i++) {
+    vector<vector<uint32_t>> d = edit_distance2_with_dp(xs.at(i), ys.at(i));
+    seq.at(i) =
+        edit_distance2_backtracking(d, xs.at(i), ys.at(i), terminal_symbol);
+  }
+  return seq;
+}
+
+vector<vector<vector<uint32_t>>> suggested_ed2_path_with_delete(
+    vector<vector<uint32_t>>& xs,
+    vector<vector<uint32_t>>& ys,
+    uint32_t terminal_symbol,
+    uint32_t deletion_symbol) {
+  vector<vector<vector<uint32_t>>> seq(xs.size());
+  for (uint32_t i = 0; i < xs.size(); i++) {
+    vector<vector<uint32_t>> d = edit_distance2_with_dp(xs.at(i), ys.at(i));
+    seq.at(i) = edit_distance2_backtracking_with_delete(
+        d, xs.at(i), ys.at(i), terminal_symbol, deletion_symbol);
+  }
+  return seq;
+}
+
+PYBIND11_MODULE(libnat, m) {
+  m.def("compute_ed2", &compute_ed2, "compute_ed2");
+  m.def("suggested_ed2_path", &suggested_ed2_path, "suggested_ed2_path");
+  m.def(
+      "suggested_ed2_path_with_delete",
+      &suggested_ed2_path_with_delete,
+      "suggested_ed2_path_with_delete");
+}

fairseq/clib/libnat_cuda/binding.cpp

@@ -0,0 +1,60 @@
+/**
+ * Copyright 2017-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+/*
+ This code is partially adpoted from https://github.com/1ytic/pytorch-edit-distance
+ */
+
+#include "edit_dist.h"
+#include <torch/types.h>
+
+#ifndef TORCH_CHECK
+#define TORCH_CHECK AT_CHECK
+#endif
+
+#define CHECK_CUDA(x) TORCH_CHECK(x.type().is_cuda(), #x " must be a CUDA tensor")
+#define CHECK_CONTIGUOUS(x) TORCH_CHECK(x.is_contiguous(), #x " must be contiguous")
+#define CHECK_INPUT(x) CHECK_CUDA(x); CHECK_CONTIGUOUS(x)
+
+
+torch::Tensor LevenshteinDistance(
+        torch::Tensor source,
+        torch::Tensor target,
+        torch::Tensor source_length,
+        torch::Tensor target_length) {
+
+    CHECK_INPUT(source);
+    CHECK_INPUT(target);
+    CHECK_INPUT(source_length);
+    CHECK_INPUT(target_length);
+    return LevenshteinDistanceCuda(source, target, source_length, target_length);
+}
+
+torch::Tensor GenerateDeletionLabel(
+        torch::Tensor source,
+        torch::Tensor operations) {
+
+    CHECK_INPUT(source);
+    CHECK_INPUT(operations);
+    return GenerateDeletionLabelCuda(source, operations);
+}
+
+std::pair<torch::Tensor, torch::Tensor> GenerateInsertionLabel(
+        torch::Tensor target,
+        torch::Tensor operations) {
+
+    CHECK_INPUT(target);
+    CHECK_INPUT(operations);
+    return GenerateInsertionLabelCuda(target, operations);
+}
+
+PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
+    m.def("levenshtein_distance", &LevenshteinDistance, "Levenshtein distance");
+    m.def("generate_deletion_labels", &GenerateDeletionLabel, "Generate Deletion Label");
+    m.def("generate_insertion_labels", &GenerateInsertionLabel, "Generate Insertion Label");
+}

fairseq/clib/libnat_cuda/edit_dist.cu

@@ -0,0 +1,332 @@
+/**
+* Copyright 2017-present, Facebook, Inc.
+* All rights reserved.
+*
+* This source code is licensed under the license found in the
+* LICENSE file in the root directory of this source tree.
+*/
+
+#include "edit_dist.h"
+#include <THC/THC.h>
+#include <cuda.h>
+#include <cuda_runtime.h>
+#include <device_launch_parameters.h>
+#include <utility>      // std::pair
+
+template <typename scalar_t>
+__global__ void generate_deletion_label_kernel(
+        const scalar_t* __restrict__ source,
+        const size_t source_size,
+        const size_t operation_size,
+        int* __restrict__ operations,
+        int* __restrict__ labels) {
+
+    const int index = blockIdx.x;
+    const int offset = index * operation_size;
+    const int offset_label = index * source_size;
+
+    for (int i = 0; i < source_size; i++) {
+        labels[offset_label + i] = 0;
+    }
+
+    int k = 0;
+    for (int i = 0; i < operation_size; i++){
+        if (operations[offset + i] == 0){
+            break;
+        } else if (operations[offset + i] == 1){
+            continue;
+        } else {
+            labels[offset_label + k] = 3 - operations[offset + i];
+            k++;
+        }
+    }
+}
+
+template <typename scalar_t>
+__global__ void generate_insertion_label_kernel(
+        const scalar_t* __restrict__ target,
+        const size_t target_size,
+        const size_t operation_size,
+        int* __restrict__ operations,
+        int* __restrict__ labels,
+        int* __restrict__ masks) {
+
+    const int index = blockIdx.x;
+    const int offset = index * operation_size;
+    const int offset_label = index * target_size;
+
+    int k = 0;
+    int u = 0;
+    int m = 0;
+
+    for (int i = 0; i < target_size; i++) {
+        labels[offset_label + i] = 0;
+        masks[offset_label + i] = 0;
+    }
+
+    for (int i = 0; i < operation_size-1; i++){
+        if (operations[offset + i] == 0){
+            break;
+        } else if (operations[offset + i] == 2){
+            continue;
+        } else if (operations[offset + i] == 1){
+            masks[offset_label + m] = 1;
+            u++; m++;
+        } else {
+            labels[offset_label + k] = u;
+            masks[offset_label + m] = 0;
+            k++; m++;
+            u = 0;
+        }
+    }
+}
+
+template <typename scalar_t>
+__global__ void levenshtein_distance_kernel(
+        const scalar_t* __restrict__ source,
+        const scalar_t* __restrict__ target,
+        const int* __restrict__ source_length,
+        const int* __restrict__ target_length,
+        const size_t source_size,
+        const size_t target_size,
+        int* __restrict__ operations,
+        int* __restrict__ errors_curr) {
+
+    const int index = blockIdx.x;
+    const int offset = index * (source_size + target_size);
+    const int d = index * (source_size + 1) * (target_size + 1);
+    const int t = target_size + 1;
+
+    auto err_idx = [d, t](int i, int j) { return d + i * t + j; };
+    auto opt_idx = [offset](int k) { return offset + k; };
+
+    const int hyp_len = source_length[index];
+    const int ref_len = target_length[index];
+    const scalar_t* hyp_begin = source + index * source_size;
+    const scalar_t* ref_begin = target + index * target_size;
+
+    // dynamic programming
+    for (int i = 0; i <= hyp_len; i++){
+        errors_curr[err_idx(i, 0)] = i;
+    }
+    for (int j = 0; j <= ref_len; j++){
+        errors_curr[err_idx(0, j)] = j;
+    }
+    for (int i = 1; i <= hyp_len; i++){
+        for (int j = 1; j <= ref_len; j++){
+            errors_curr[err_idx(i, j)] = min(
+                min(
+                    errors_curr[err_idx(i-1, j)],
+                    errors_curr[err_idx(i, j-1)]
+                ) + 1,
+                errors_curr[err_idx(i-1, j-1)] + 2 * (
+                    *(hyp_begin+i-1) == *(ref_begin+j-1) ? 0 : 1
+                )
+            );
+        }
+    }
+
+    // back-tracing
+    int i = hyp_len;
+    int j = ref_len;
+    int o = hyp_len + ref_len;
+
+    for (int k = 0; k < source_size + target_size; k++) {
+        operations[opt_idx(k)] = 0;
+    }
+
+    while ((i >= 0) && (j >= 0)) {
+        if ((i == 0) && (j == 0)) {
+        break;
+        }
+
+        if ((j > 0) && (errors_curr[err_idx(i, j-1)] < errors_curr[err_idx(i, j)])) {
+            o--; operations[opt_idx(o)] = 1; j--;  // insertion
+        } else if ((i > 0) && (errors_curr[err_idx(i-1, j)] < errors_curr[err_idx(i, j)])) {
+            o--; operations[opt_idx(o)] = 2; i--;  // deletion
+        } else {
+            o--; operations[opt_idx(o)] = 3; i--; j--;  // do nothing
+        }
+    }
+
+    // moving to the left
+    for (int k = 0; k < hyp_len + ref_len; k++) {
+        if (k + o < hyp_len + ref_len){
+            operations[opt_idx(k)] = operations[opt_idx(k+o)];
+        } else{
+            operations[opt_idx(k)] = 0;  // padding
+        }
+    }
+
+}
+
+template <typename scalar_t>
+__global__ void faster_levenshtein_distance_kernel(
+        const scalar_t* __restrict__ source,
+        const scalar_t* __restrict__ target,
+        const int* __restrict__ source_length,
+        const int* __restrict__ target_length,
+        const size_t source_size,
+        const size_t target_size,
+        int* __restrict__ operations) {
+
+    extern __shared__ short errors[];
+    auto errors_curr = errors;
+
+    const int index = blockIdx.x;
+    const int offset = index * (source_size + target_size);
+    const int t = target_size + 1;
+
+    auto err_idx = [t](int i, int j) { return i * t + j; };
+    auto opt_idx = [offset](int k) { return offset + k; };
+
+    const int hyp_len = source_length[index];
+    const int ref_len = target_length[index];
+    const scalar_t* hyp_begin = source + index * source_size;
+    const scalar_t* ref_begin = target + index * target_size;
+
+    // dynamic programming
+    for (int i = 0; i <= hyp_len; i++){
+        errors_curr[err_idx(i, 0)] = i;
+    }
+    for (int j = 0; j <= ref_len; j++){
+        errors_curr[err_idx(0, j)] = j;
+    }
+    for (int i = 1; i <= hyp_len; i++){
+        for (int j = 1; j <= ref_len; j++){
+            errors_curr[err_idx(i, j)] = min(
+                min(
+                    errors_curr[err_idx(i-1, j)],
+                    errors_curr[err_idx(i, j-1)]
+                ) + 1,
+                errors_curr[err_idx(i-1, j-1)] + 2 * (
+                    *(hyp_begin+i-1) == *(ref_begin+j-1) ? 0 : 1
+                )
+            );
+        }
+    }
+
+    // back-tracing
+    int i = hyp_len;
+    int j = ref_len;
+    int o = hyp_len + ref_len;
+
+    for (int k = 0; k < source_size + target_size; k++) {
+        operations[opt_idx(k)] = 0;
+    }
+
+    while ((i >= 0) && (j >= 0)) {
+        if ((i == 0) && (j == 0)) {
+        break;
+        }
+
+        if ((j > 0) && (errors_curr[err_idx(i, j-1)] < errors_curr[err_idx(i, j)])) {
+            o--; operations[opt_idx(o)] = 1; j--;  // insertion
+        } else if ((i > 0) && (errors_curr[err_idx(i-1, j)] < errors_curr[err_idx(i, j)])) {
+            o--; operations[opt_idx(o)] = 2; i--;  // deletion
+        } else {
+            o--; operations[opt_idx(o)] = 3; i--; j--;  // do nothing
+        }
+    }
+
+    // moving to the left
+    for (int k = 0; k < hyp_len + ref_len; k++) {
+        if (k + o < hyp_len + ref_len){
+            operations[opt_idx(k)] = operations[opt_idx(k+o)];
+        } else{
+            operations[opt_idx(k)] = 0;  // padding
+        }
+    }
+
+}
+
+
+torch::Tensor GenerateDeletionLabelCuda(
+        torch::Tensor source,
+        torch::Tensor operations) {
+
+    const auto batch_size = source.size(0);
+    at::TensorOptions options(source.device());
+    options = options.dtype(at::ScalarType::Int);
+    auto labels = torch::empty({batch_size, source.size(1)}, options);
+    auto stream = at::cuda::getCurrentCUDAStream(source.device().index());
+
+    AT_DISPATCH_ALL_TYPES(source.scalar_type(), "generate_deletion_labels", ([&] {
+        generate_deletion_label_kernel<scalar_t><<<batch_size, 1, 0, stream>>>(
+            source.data_ptr<scalar_t>(),
+            source.size(1),
+            operations.size(1),
+            operations.data_ptr<int>(),
+            labels.data_ptr<int>());
+    }));
+
+    return labels;
+}
+
+std::pair<torch::Tensor, torch::Tensor> GenerateInsertionLabelCuda(
+    torch::Tensor target,
+    torch::Tensor operations) {
+
+const auto batch_size = target.size(0);
+at::TensorOptions options(target.device());
+options = options.dtype(at::ScalarType::Int);
+auto labels = torch::empty({batch_size, target.size(1)}, options);
+auto masks  = torch::empty({batch_size, target.size(1)}, options);
+auto stream = at::cuda::getCurrentCUDAStream(target.device().index());
+
+AT_DISPATCH_ALL_TYPES(target.scalar_type(), "generate_insertion_labels", ([&] {
+    generate_insertion_label_kernel<scalar_t><<<batch_size, 1, 0, stream>>>(
+        target.data_ptr<scalar_t>(),
+        target.size(1),
+        operations.size(1),
+        operations.data_ptr<int>(),
+        labels.data_ptr<int>(),
+        masks.data_ptr<int>());
+}));
+
+return std::make_pair(labels, masks);
+}
+
+
+torch::Tensor LevenshteinDistanceCuda(
+        torch::Tensor source,
+        torch::Tensor target,
+        torch::Tensor source_length,
+        torch::Tensor target_length) {
+
+    const auto batch_size = source.size(0);
+    const auto shared_size = (source.size(1) + 1) * (target.size(1) + 1) * sizeof(short);
+    
+    at::TensorOptions options(source.device());
+    options = options.dtype(at::ScalarType::Int);
+    auto operations = torch::empty({batch_size, source.size(1) + target.size(1)}, options);
+    auto stream = at::cuda::getCurrentCUDAStream(source.device().index());
+
+    if (shared_size > 40000) {
+        auto distances = torch::empty({batch_size, (source.size(1) + 1) * (target.size(1) + 1)}, options);
+        AT_DISPATCH_ALL_TYPES(source.scalar_type(), "levenshtein_distance", ([&] {
+            levenshtein_distance_kernel<scalar_t><<<batch_size, 1, 0, stream>>>(
+                source.data_ptr<scalar_t>(),
+                target.data_ptr<scalar_t>(),
+                source_length.data_ptr<int>(),
+                target_length.data_ptr<int>(),
+                source.size(1),
+                target.size(1),
+                operations.data_ptr<int>(),
+                distances.data_ptr<int>());
+        }));
+    } else {
+        AT_DISPATCH_ALL_TYPES(source.scalar_type(), "faster_levenshtein_distance", ([&] {
+            faster_levenshtein_distance_kernel<scalar_t><<<batch_size, 1, shared_size, stream>>>(
+                source.data_ptr<scalar_t>(),
+                target.data_ptr<scalar_t>(),
+                source_length.data_ptr<int>(),
+                target_length.data_ptr<int>(),
+                source.size(1),
+                target.size(1),
+                operations.data_ptr<int>());
+        }));
+    }
+
+    return operations;
+}

fairseq/clib/libnat_cuda/edit_dist.h

@@ -0,0 +1,25 @@
+/**
+ * Copyright 2017-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <torch/extension.h>
+
+torch::Tensor LevenshteinDistanceCuda(
+        torch::Tensor source,
+        torch::Tensor target,
+        torch::Tensor source_length,
+        torch::Tensor target_length);
+
+torch::Tensor GenerateDeletionLabelCuda(
+        torch::Tensor source,
+        torch::Tensor operations);
+
+std::pair<torch::Tensor, torch::Tensor> GenerateInsertionLabelCuda(
+        torch::Tensor source,
+        torch::Tensor operations);

fairseq/criterions/__init__.py

@@ -0,0 +1,36 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+"""isort:skip_file"""
+
+import importlib
+import os
+
+from fairseq import registry
+from fairseq.criterions.fairseq_criterion import (  # noqa
+    FairseqCriterion,
+    LegacyFairseqCriterion,
+)
+from omegaconf import DictConfig
+
+
+(
+    build_criterion_,
+    register_criterion,
+    CRITERION_REGISTRY,
+    CRITERION_DATACLASS_REGISTRY,
+) = registry.setup_registry(
+    "--criterion", base_class=FairseqCriterion, default="cross_entropy"
+)
+
+
+def build_criterion(cfg: DictConfig, task):
+    return build_criterion_(cfg, task)
+
+
+# automatically import any Python files in the criterions/ directory
+for file in os.listdir(os.path.dirname(__file__)):
+    if file.endswith(".py") and not file.startswith("_"):
+        file_name = file[: file.find(".py")]
+        importlib.import_module("fairseq.criterions." + file_name)

fairseq/criterions/ctc.py

@@ -0,0 +1,263 @@
+# All rights reserved.
+#
+# This source code is licensed under the license found in the LICENSE file in
+# the root directory of this source tree. An additional grant of patent rights
+# can be found in the PATENTS file in the same directory.
+
+import math
+from argparse import Namespace
+
+import torch
+import torch.nn.functional as F
+from fairseq import metrics, utils
+from fairseq.criterions import LegacyFairseqCriterion, register_criterion
+from fairseq.data.data_utils import post_process
+from fairseq.logging.meters import safe_round
+
+
+@register_criterion("ctc")
+class CtcCriterion(LegacyFairseqCriterion):
+    def __init__(self, args, task):
+        super().__init__(args, task)
+        self.blank_idx = task.target_dictionary.bos()
+        self.pad_idx = task.target_dictionary.pad()
+        self.eos_idx = task.target_dictionary.eos()
+        self.post_process = args.post_process
+
+        if args.wer_args is not None:
+            from examples.speech_recognition.w2l_decoder import W2lKenLMDecoder
+
+            wer_compute_kenlm, wer_lexicon, lm_w, ws_w = eval(args.wer_args)
+
+            dec_args = Namespace()
+            dec_args.nbest = 1
+            dec_args.criterion = "ctc"
+            dec_args.kenlm_model = wer_compute_kenlm
+            dec_args.lexicon = wer_lexicon
+            dec_args.beam = 50
+            dec_args.beam_size_token = min(50, len(task.target_dictionary))
+            dec_args.beam_threshold = min(50, len(task.target_dictionary))
+            dec_args.lm_weight = lm_w
+            dec_args.word_score = ws_w
+            dec_args.unk_weight = -math.inf
+            dec_args.sil_weight = 0
+
+            self.w2l_decoder = W2lKenLMDecoder(dec_args, task.target_dictionary)
+        else:
+            self.w2l_decoder = None
+
+        self.zero_infinity = args.zero_infinity
+        self.sentence_avg = args.sentence_avg
+
+    @staticmethod
+    def add_args(parser):
+        """Add criterion-specific arguments to the parser."""
+        parser.add_argument(
+            "--zero-infinity", action="store_true", help="zero inf loss"
+        )
+        try:
+            parser.add_argument(
+                "--post-process",
+                "--remove-bpe",
+                default="letter",
+                help="remove BPE tokens before scoring (can be set to sentencepiece, letter, and more)",
+            )
+        except:
+            pass  # this option might have been added from eval args
+        parser.add_argument(
+            "--wer-args",
+            type=str,
+            default=None,
+            help="options for wer computation on valid set using 4 gram lm. this should be a tuple of 4 elements: path to 4-gram lm, \
+            path to lexicon, lm score, word score",
+        )
+
+    def get_net_output(self, model, sample):
+        net_output = model(**sample["net_input"])
+        return net_output
+
+    def get_loss(self, model, sample, net_output, reduce=True):
+        lprobs = model.get_normalized_probs(
+            net_output, log_probs=True
+        ).contiguous()  # (T, B, C) from the encoder
+
+        if "src_lengths" in sample["net_input"]:
+            input_lengths = sample["net_input"]["src_lengths"]
+        else:
+            non_padding_mask = ~net_output["padding_mask"]
+            input_lengths = non_padding_mask.long().sum(-1)
+
+        pad_mask = (sample["target"] != self.pad_idx) & (
+            sample["target"] != self.eos_idx
+        )
+        targets_flat = sample["target"].masked_select(pad_mask)
+        target_lengths = sample["target_lengths"]
+
+        with torch.backends.cudnn.flags(enabled=False):
+            loss = F.ctc_loss(
+                lprobs,
+                targets_flat,
+                input_lengths,
+                target_lengths,
+                blank=self.blank_idx,
+                reduction="sum",
+                zero_infinity=self.zero_infinity,
+            )
+
+        ntokens = (
+            sample["ntokens"] if "ntokens" in sample else target_lengths.sum().item()
+        )
+
+        sample_size = sample["target"].size(0) if self.sentence_avg else ntokens
+        logging_output = {
+            "loss": utils.item(loss.data),  # * sample['ntokens'],
+            "ntokens": ntokens,
+            "nsentences": sample["id"].numel(),
+            "sample_size": sample_size,
+        }
+
+        if not model.training:
+            import editdistance
+
+            with torch.no_grad():
+                lprobs_t = lprobs.transpose(0, 1).float().contiguous().cpu()
+
+                c_err = 0
+                c_len = 0
+                w_errs = 0
+                w_len = 0
+                wv_errs = 0
+                for lp, t, inp_l in zip(
+                    lprobs_t,
+                    sample["target_label"]
+                    if "target_label" in sample
+                    else sample["target"],
+                    input_lengths,
+                ):
+                    lp = lp[:inp_l].unsqueeze(0)
+
+                    decoded = None
+                    if self.w2l_decoder is not None:
+                        decoded = self.w2l_decoder.decode(lp)
+                        if len(decoded) < 1:
+                            decoded = None
+                        else:
+                            decoded = decoded[0]
+                            if len(decoded) < 1:
+                                decoded = None
+                            else:
+                                decoded = decoded[0]
+
+                    p = (t != self.task.target_dictionary.pad()) & (
+                        t != self.task.target_dictionary.eos()
+                    )
+                    targ = t[p]
+                    targ_units = self.task.target_dictionary.string(targ)
+                    targ_units_arr = targ.tolist()
+
+                    toks = lp.argmax(dim=-1).unique_consecutive()
+                    pred_units_arr = toks[toks != self.blank_idx].tolist()
+
+                    c_err += editdistance.eval(pred_units_arr, targ_units_arr)
+                    c_len += len(targ_units_arr)
+
+                    targ_words = post_process(targ_units, self.post_process).split()
+
+                    pred_units = self.task.target_dictionary.string(pred_units_arr)
+                    pred_words_raw = post_process(pred_units, self.post_process).split()
+
+                    if decoded is not None and "words" in decoded:
+                        pred_words = decoded["words"]
+                        w_errs += editdistance.eval(pred_words, targ_words)
+                        wv_errs += editdistance.eval(pred_words_raw, targ_words)
+                    else:
+                        dist = editdistance.eval(pred_words_raw, targ_words)
+                        w_errs += dist
+                        wv_errs += dist
+
+                    w_len += len(targ_words)
+
+                logging_output["wv_errors"] = wv_errs
+                logging_output["w_errors"] = w_errs
+                logging_output["w_total"] = w_len
+                logging_output["c_errors"] = c_err
+                logging_output["c_total"] = c_len
+
+        return loss, sample_size, logging_output
+
+    def forward(self, model, sample, reduce=True):
+        import pdb
+        net_output = self.get_net_output(model, sample)
+        loss, sample_size, logging_output = self.get_loss(model, sample, net_output, reduce)
+
+        return loss, sample_size, logging_output
+
+    @staticmethod
+    def reduce_metrics(logging_outputs) -> None:
+        """Aggregate logging outputs from data parallel training."""
+
+        loss_sum = utils.item(sum(log.get("loss", 0) for log in logging_outputs))
+        ntokens = utils.item(sum(log.get("ntokens", 0) for log in logging_outputs))
+        nsentences = utils.item(
+            sum(log.get("nsentences", 0) for log in logging_outputs)
+        )
+        sample_size = utils.item(
+            sum(log.get("sample_size", 0) for log in logging_outputs)
+        )
+
+        metrics.log_scalar(
+            "loss", loss_sum / sample_size / math.log(2), sample_size, round=3
+        )
+        metrics.log_scalar("ntokens", ntokens)
+        metrics.log_scalar("nsentences", nsentences)
+        if sample_size != ntokens:
+            metrics.log_scalar(
+                "nll_loss", loss_sum / ntokens / math.log(2), ntokens, round=3
+            )
+
+        c_errors = sum(log.get("c_errors", 0) for log in logging_outputs)
+        metrics.log_scalar("_c_errors", c_errors)
+        c_total = sum(log.get("c_total", 0) for log in logging_outputs)
+        metrics.log_scalar("_c_total", c_total)
+        w_errors = sum(log.get("w_errors", 0) for log in logging_outputs)
+        metrics.log_scalar("_w_errors", w_errors)
+        wv_errors = sum(log.get("wv_errors", 0) for log in logging_outputs)
+        metrics.log_scalar("_wv_errors", wv_errors)
+        w_total = sum(log.get("w_total", 0) for log in logging_outputs)
+        metrics.log_scalar("_w_total", w_total)
+
+        if c_total > 0:
+            metrics.log_derived(
+                "uer",
+                lambda meters: safe_round(
+                    meters["_c_errors"].sum * 100.0 / meters["_c_total"].sum, 3
+                )
+                if meters["_c_total"].sum > 0
+                else float("nan"),
+            )
+        if w_total > 0:
+            metrics.log_derived(
+                "wer",
+                lambda meters: safe_round(
+                    meters["_w_errors"].sum * 100.0 / meters["_w_total"].sum, 3
+                )
+                if meters["_w_total"].sum > 0
+                else float("nan"),
+            )
+            metrics.log_derived(
+                "raw_wer",
+                lambda meters: safe_round(
+                    meters["_wv_errors"].sum * 100.0 / meters["_w_total"].sum, 3
+                )
+                if meters["_w_total"].sum > 0
+                else float("nan"),
+            )
+
+    @staticmethod
+    def logging_outputs_can_be_summed() -> bool:
+        """
+        Whether the logging outputs returned by `forward` can be summed
+        across workers prior to calling `reduce_metrics`. Setting this
+        to True will improves distributed training speed.
+        """
+        return True

fairseq/criterions/fairseq_criterion.py

@@ -0,0 +1,118 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import inspect
+from typing import Any, Dict, List
+
+from fairseq import metrics, utils
+from fairseq.dataclass.utils import gen_parser_from_dataclass
+from omegaconf import DictConfig
+from torch.nn.modules.loss import _Loss
+
+
+class FairseqCriterion(_Loss):
+    def __init__(self, task):
+        super().__init__()
+        self.task = task
+        if hasattr(task, "target_dictionary"):
+            tgt_dict = task.target_dictionary
+            self.padding_idx = tgt_dict.pad() if tgt_dict is not None else -100
+
+    @classmethod
+    def add_args(cls, parser):
+        """Add criterion-specific arguments to the parser."""
+        dc = getattr(cls, "__dataclass", None)
+        if dc is not None:
+            gen_parser_from_dataclass(parser, dc())
+
+    @classmethod
+    def build_criterion(cls, cfg: DictConfig, task):
+        """Construct a criterion from command-line args."""
+        # arguments in the __init__.
+        init_args = {}
+        for p in inspect.signature(cls).parameters.values():
+            if (
+                p.kind == p.POSITIONAL_ONLY
+                or p.kind == p.VAR_POSITIONAL
+                or p.kind == p.VAR_KEYWORD
+            ):
+                # we haven't implemented inference for these argument types,
+                # but PRs welcome :)
+                raise NotImplementedError("{} not supported".format(p.kind))
+
+            assert p.kind in {p.POSITIONAL_OR_KEYWORD, p.KEYWORD_ONLY}
+
+            if p.name == "task":
+                init_args["task"] = task
+            elif hasattr(cfg, p.name):
+                init_args[p.name] = getattr(cfg, p.name)
+            elif p.default != p.empty:
+                pass  # we'll use the default value
+            else:
+                raise NotImplementedError(
+                    "Unable to infer Criterion arguments, please implement "
+                    "{}.build_criterion".format(cls.__name__)
+                )
+        return cls(**init_args)
+
+    def forward(self, model, sample, reduce=True):
+        """Compute the loss for the given sample.
+
+        Returns a tuple with three elements:
+        1) the loss
+        2) the sample size, which is used as the denominator for the gradient
+        3) logging outputs to display while training
+        """
+        raise NotImplementedError
+
+    @staticmethod
+    def aggregate_logging_outputs(
+        logging_outputs: List[Dict[str, Any]]
+    ) -> Dict[str, Any]:
+        """Aggregate logging outputs from data parallel training."""
+        utils.deprecation_warning(
+            "The aggregate_logging_outputs API is deprecated. "
+            "Please use the reduce_metrics API instead."
+        )
+        raise NotImplementedError
+
+    @classmethod
+    def reduce_metrics(cls, logging_outputs: List[Dict[str, Any]]) -> None:
+        """Aggregate logging outputs from data parallel training."""
+        utils.deprecation_warning(
+            "Criterions should implement the reduce_metrics API. "
+            "Falling back to deprecated aggregate_logging_outputs API."
+        )
+        agg_logging_outputs = cls.aggregate_logging_outputs(logging_outputs)
+        for k, v in agg_logging_outputs.items():
+            if k in {"nsentences", "ntokens", "sample_size"}:
+                continue
+            metrics.log_scalar(k, v)
+
+    @staticmethod
+    def logging_outputs_can_be_summed() -> bool:
+        """
+        Whether the logging outputs returned by `forward` can be summed
+        across workers prior to calling `reduce_metrics`. Setting this
+        to True will improves distributed training speed.
+        """
+        return False
+
+
+class LegacyFairseqCriterion(FairseqCriterion):
+    def __init__(self, args, task):
+        super().__init__(task=task)
+        self.args = args
+
+        utils.deprecation_warning(
+            "Criterions should take explicit arguments instead of an "
+            "argparse.Namespace object, please update your criterion by "
+            "extending FairseqCriterion instead of LegacyFairseqCriterion."
+        )
+
+    @classmethod
+    def build_criterion(cls, args, task):
+        """Construct a criterion from command-line args."""
+        return cls(args, task)

fairseq/criterions/label_smoothed_cross_entropy.py

@@ -0,0 +1,160 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import math
+
+import torch
+from fairseq import metrics, utils
+from fairseq.criterions import FairseqCriterion, register_criterion
+
+
+def label_smoothed_nll_loss(lprobs, target, epsilon, ignore_index=None, reduce=True):
+    if target.dim() == lprobs.dim() - 1:
+        target = target.unsqueeze(-1)
+    nll_loss = -lprobs.gather(dim=-1, index=target)
+    smooth_loss = -lprobs.sum(dim=-1, keepdim=True)
+    if ignore_index is not None:
+        pad_mask = target.eq(ignore_index)
+        nll_loss.masked_fill_(pad_mask, 0.0)
+        smooth_loss.masked_fill_(pad_mask, 0.0)
+    else:
+        nll_loss = nll_loss.squeeze(-1)
+        smooth_loss = smooth_loss.squeeze(-1)
+    if reduce:
+        nll_loss = nll_loss.sum()
+        smooth_loss = smooth_loss.sum()
+    eps_i = epsilon / lprobs.size(-1)
+    loss = (1.0 - epsilon) * nll_loss + eps_i * smooth_loss
+    return loss, nll_loss
+
+
+@register_criterion("label_smoothed_cross_entropy")
+class LabelSmoothedCrossEntropyCriterion(FairseqCriterion):
+    def __init__(
+        self,
+        task,
+        sentence_avg,
+        label_smoothing,
+        ignore_prefix_size=0,
+        report_accuracy=False,
+    ):
+        super().__init__(task)
+        self.sentence_avg = sentence_avg
+        self.eps = label_smoothing
+        self.ignore_prefix_size = ignore_prefix_size
+        self.report_accuracy = report_accuracy
+
+    @staticmethod
+    def add_args(parser):
+        """Add criterion-specific arguments to the parser."""
+        # fmt: off
+        parser.add_argument('--label-smoothing', default=0., type=float, metavar='D',
+                            help='epsilon for label smoothing, 0 means no label smoothing')
+        parser.add_argument('--report-accuracy', action='store_true',
+                            help='report accuracy metric')
+        parser.add_argument('--ignore-prefix-size', default=0, type=int,
+                            help='Ignore first N tokens')
+        # fmt: on
+
+    def forward(self, model, sample, reduce=True):
+        """Compute the loss for the given sample.
+
+        Returns a tuple with three elements:
+        1) the loss
+        2) the sample size, which is used as the denominator for the gradient
+        3) logging outputs to display while training
+        """
+        net_output = model(**sample["net_input"])
+        loss, nll_loss = self.compute_loss(model, net_output, sample, reduce=reduce)
+        sample_size = (
+            sample["target"].size(0) if self.sentence_avg else sample["ntokens"]
+        )
+        logging_output = {
+            "loss": loss.data,
+            "nll_loss": nll_loss.data,
+            "ntokens": sample["ntokens"],
+            "nsentences": sample["target"].size(0),
+            "sample_size": sample_size,
+        }
+        if self.report_accuracy:
+            n_correct, total = self.compute_accuracy(model, net_output, sample)
+            logging_output["n_correct"] = utils.item(n_correct.data)
+            logging_output["total"] = utils.item(total.data)
+        return loss, sample_size, logging_output
+
+    def get_lprobs_and_target(self, model, net_output, sample):
+        lprobs = model.get_normalized_probs(net_output, log_probs=True)
+        target = model.get_targets(sample, net_output)
+        if self.ignore_prefix_size > 0:
+            if getattr(lprobs, "batch_first", False):
+                lprobs = lprobs[:, self.ignore_prefix_size :, :].contiguous()
+                target = target[:, self.ignore_prefix_size :].contiguous()
+            else:
+                lprobs = lprobs[self.ignore_prefix_size :, :, :].contiguous()
+                target = target[self.ignore_prefix_size :, :].contiguous()
+        return lprobs.view(-1, lprobs.size(-1)), target.view(-1)
+
+    def compute_loss(self, model, net_output, sample, reduce=True):
+        lprobs, target = self.get_lprobs_and_target(model, net_output, sample)
+        loss, nll_loss = label_smoothed_nll_loss(
+            lprobs,
+            target,
+            self.eps,
+            ignore_index=self.padding_idx,
+            reduce=reduce,
+        )
+        return loss, nll_loss
+
+    def compute_accuracy(self, model, net_output, sample):
+        lprobs, target = self.get_lprobs_and_target(model, net_output, sample)
+        mask = target.ne(self.padding_idx)
+        n_correct = torch.sum(
+            lprobs.argmax(1).masked_select(mask).eq(target.masked_select(mask))
+        )
+        total = torch.sum(mask)
+        return n_correct, total
+
+    @classmethod
+    def reduce_metrics(cls, logging_outputs) -> None:
+        """Aggregate logging outputs from data parallel training."""
+        loss_sum = sum(log.get("loss", 0) for log in logging_outputs)
+        nll_loss_sum = sum(log.get("nll_loss", 0) for log in logging_outputs)
+        ntokens = sum(log.get("ntokens", 0) for log in logging_outputs)
+        sample_size = sum(log.get("sample_size", 0) for log in logging_outputs)
+
+        metrics.log_scalar(
+            "loss", loss_sum / sample_size / math.log(2), sample_size, round=3
+        )
+        metrics.log_scalar(
+            "nll_loss", nll_loss_sum / ntokens / math.log(2), ntokens, round=3
+        )
+        metrics.log_derived(
+            "ppl", lambda meters: utils.get_perplexity(meters["nll_loss"].avg)
+        )
+
+        total = utils.item(sum(log.get("total", 0) for log in logging_outputs))
+        if total > 0:
+            metrics.log_scalar("total", total)
+            n_correct = utils.item(
+                sum(log.get("n_correct", 0) for log in logging_outputs)
+            )
+            metrics.log_scalar("n_correct", n_correct)
+            metrics.log_derived(
+                "accuracy",
+                lambda meters: round(
+                    meters["n_correct"].sum * 100.0 / meters["total"].sum, 3
+                )
+                if meters["total"].sum > 0
+                else float("nan"),
+            )
+
+    @staticmethod
+    def logging_outputs_can_be_summed() -> bool:
+        """
+        Whether the logging outputs returned by `forward` can be summed
+        across workers prior to calling `reduce_metrics`. Setting this
+        to True will improves distributed training speed.
+        """
+        return True

fairseq/criterions/label_smoothed_cross_entropy_with_alignment.py

@@ -0,0 +1,125 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import math
+
+from fairseq import metrics, utils
+from fairseq.criterions import register_criterion
+
+from .label_smoothed_cross_entropy import LabelSmoothedCrossEntropyCriterion
+
+
+@register_criterion("label_smoothed_cross_entropy_with_alignment")
+class LabelSmoothedCrossEntropyCriterionWithAlignment(
+    LabelSmoothedCrossEntropyCriterion
+):
+    def __init__(self, task, sentence_avg, label_smoothing, alignment_lambda):
+        super().__init__(task, sentence_avg, label_smoothing)
+        self.alignment_lambda = alignment_lambda
+
+    @staticmethod
+    def add_args(parser):
+        """Add criterion-specific arguments to the parser."""
+        LabelSmoothedCrossEntropyCriterion.add_args(parser)
+        parser.add_argument(
+            "--alignment-lambda",
+            default=0.05,
+            type=float,
+            metavar="D",
+            help="weight for the alignment loss",
+        )
+
+    def forward(self, model, sample, reduce=True):
+        """Compute the loss for the given sample.
+
+        Returns a tuple with three elements:
+        1) the loss
+        2) the sample size, which is used as the denominator for the gradient
+        3) logging outputs to display while training
+        """
+        net_output = model(**sample["net_input"])
+        loss, nll_loss = self.compute_loss(model, net_output, sample, reduce=reduce)
+        sample_size = (
+            sample["target"].size(0) if self.sentence_avg else sample["ntokens"]
+        )
+        logging_output = {
+            "loss": utils.item(loss.data) if reduce else loss.data,
+            "nll_loss": utils.item(nll_loss.data) if reduce else nll_loss.data,
+            "ntokens": sample["ntokens"],
+            "nsentences": sample["target"].size(0),
+            "sample_size": sample_size,
+        }
+
+        alignment_loss = None
+
+        # Compute alignment loss only for training set and non dummy batches.
+        if "alignments" in sample and sample["alignments"] is not None:
+            alignment_loss = self.compute_alignment_loss(sample, net_output)
+
+        if alignment_loss is not None:
+            logging_output["alignment_loss"] = utils.item(alignment_loss.data)
+            loss += self.alignment_lambda * alignment_loss
+
+        return loss, sample_size, logging_output
+
+    def compute_alignment_loss(self, sample, net_output):
+        attn_prob = net_output[1]["attn"][0]
+        bsz, tgt_sz, src_sz = attn_prob.shape
+        attn = attn_prob.view(bsz * tgt_sz, src_sz)
+
+        align = sample["alignments"]
+        align_weights = sample["align_weights"].float()
+
+        if len(align) > 0:
+            # Alignment loss computation. align (shape [:, 2]) contains the src-tgt index pairs corresponding to
+            # the alignments. align_weights (shape [:]) contains the 1 / frequency of a tgt index for normalizing.
+            loss = -(
+                (attn[align[:, 1][:, None], align[:, 0][:, None]]).log()
+                * align_weights[:, None]
+            ).sum()
+        else:
+            return None
+
+        return loss
+
+    @staticmethod
+    def reduce_metrics(logging_outputs) -> None:
+        """Aggregate logging outputs from data parallel training."""
+        loss_sum = utils.item(sum(log.get("loss", 0) for log in logging_outputs))
+        nll_loss_sum = utils.item(
+            sum(log.get("nll_loss", 0) for log in logging_outputs)
+        )
+        alignment_loss_sum = utils.item(
+            sum(log.get("alignment_loss", 0) for log in logging_outputs)
+        )
+        ntokens = utils.item(sum(log.get("ntokens", 0) for log in logging_outputs))
+        sample_size = utils.item(
+            sum(log.get("sample_size", 0) for log in logging_outputs)
+        )
+
+        metrics.log_scalar(
+            "loss", loss_sum / sample_size / math.log(2), sample_size, round=3
+        )
+        metrics.log_scalar(
+            "nll_loss", nll_loss_sum / ntokens / math.log(2), ntokens, round=3
+        )
+        metrics.log_scalar(
+            "alignment_loss",
+            alignment_loss_sum / sample_size / math.log(2),
+            sample_size,
+            round=3,
+        )
+        metrics.log_derived(
+            "ppl", lambda meters: utils.get_perplexity(meters["nll_loss"].avg)
+        )
+
+    @staticmethod
+    def logging_outputs_can_be_summed() -> bool:
+        """
+        Whether the logging outputs returned by `forward` can be summed
+        across workers prior to calling `reduce_metrics`. Setting this
+        to True will improves distributed training speed.
+        """
+        return True

fairseq/criterions/wav2vec_criterion.py

@@ -0,0 +1,192 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import math
+
+import torch
+import torch.nn.functional as F
+from fairseq import metrics, utils
+from fairseq.criterions import FairseqCriterion, register_criterion
+from fairseq.logging.meters import safe_round
+
+
+@register_criterion("wav2vec")
+class Wav2vecCriterion(FairseqCriterion):
+    def __init__(self, task, infonce=False, loss_weights=None, log_keys=None):
+        super().__init__(task)
+        self.infonce = infonce
+        self.loss_weights = None if loss_weights is None else eval(loss_weights)
+        self.log_keys = [] if log_keys is None else eval(log_keys)
+
+    @staticmethod
+    def add_args(parser):
+        """Add criterion-specific arguments to the parser."""
+        # fmt: off
+        parser.add_argument('--infonce', action='store_true',
+                            help='if set, uses cross entropy instead of binary cross entropy (i.e. InfoNCE loss)')
+        parser.add_argument('--loss-weights', type=str, default=None,
+                            help='weights for additional loss terms (not first one)')
+        parser.add_argument('--log-keys', type=str, default=None,
+                            help='output keys to log')
+        # fmt: on
+
+    def get_net_output(self, model, sample):
+        """Compute the loss for the given sample.
+
+        Returns a tuple with three elements:
+        1) the loss
+        2) the sample size, which is used as the denominator for the gradient
+        3) logging outputs to display while training
+        """
+        net_output = model(**sample["net_input"])
+        return net_output
+
+    def get_loss(self, model, sample, net_output, reduce=True, log_pred=False):
+        logits = model.get_logits(net_output).float()
+        target = model.get_targets(sample, net_output)
+
+        weights = None
+        if hasattr(model, "get_target_weights") and not self.infonce:
+            weights = model.get_target_weights(target, net_output)
+            if torch.is_tensor(weights):
+                weights = weights.float()
+
+        losses = []
+
+        if self.infonce:
+            loss = F.cross_entropy(
+                logits,
+                target,
+                reduction="sum" if reduce else "none",
+            )
+        else:
+            loss = F.binary_cross_entropy_with_logits(
+                logits,
+                target.float(),
+                weights,
+                reduction="sum" if reduce else "none",
+            )
+
+        sample_size = target.numel() if self.infonce else target.long().sum().item()
+        losses.append(loss.detach().clone())
+
+        if self.loss_weights is not None:
+            assert hasattr(model, "get_extra_losses")
+            extra_losses = model.get_extra_losses(net_output)
+            if torch.is_tensor(extra_losses):
+                extra_losses = [extra_losses]
+            if len(self.loss_weights) == 1 and len(extra_losses) != 1:
+                self.loss_weights = [self.loss_weights[0]] * len(extra_losses)
+            assert len(extra_losses) == len(
+                self.loss_weights
+            ), f"{len(extra_losses)}, {len(self.loss_weights)}"
+            for p, coef in zip(extra_losses, self.loss_weights):
+                if coef != 0 and p is not None:
+                    p = coef * p.float() * sample_size
+                    loss += p
+                    losses.append(p)
+
+        logging_output = {
+            "loss": loss.item() if reduce else loss,
+            "ntokens": sample_size,
+            "nsentences": sample["id"].numel(),
+            "sample_size": sample_size,
+        }
+
+        for lk in self.log_keys:
+            if lk in net_output:
+                logging_output[lk] = float((net_output[lk]))
+
+        if len(losses) > 1:
+            for i, l in enumerate(losses):
+                logging_output[f"loss_{i}"] = l.item()
+
+        if self.infonce:
+            with torch.no_grad():
+                if logits.numel() == 0:
+                    corr = 0
+                    count = 0
+                else:
+                    assert logits.dim() > 1, logits.shape
+                    max = logits.argmax(-1) == 0
+                    min = logits.argmin(-1) == 0
+                    both = max & min
+                    corr = max.long().sum().item() - both.long().sum().item()
+                    count = max.numel()
+
+                logging_output["correct"] = corr
+                logging_output["count"] = count
+
+        if log_pred:
+            logging_output["logits"] = logits.cpu().numpy()
+            logging_output["target"] = target.cpu().numpy()
+        return loss, sample_size, logging_output
+
+    def forward(self, model, sample, reduce=True, log_pred=False):
+        net_output = self.get_net_output(model, sample)
+        loss, sample_size, logging_output = self.get_loss(model, sample, net_output, reduce, log_pred)
+        return loss, sample_size, logging_output
+
+    @staticmethod
+    def reduce_metrics(logging_outputs) -> None:
+        """Aggregate logging outputs from data parallel training."""
+        loss_sum = utils.item(sum(log.get("loss", 0) for log in logging_outputs))
+        ntokens = utils.item(sum(log.get("ntokens", 0) for log in logging_outputs))
+        nsentences = utils.item(
+            sum(log.get("nsentences", 0) for log in logging_outputs)
+        )
+        sample_size = utils.item(
+            sum(log.get("sample_size", 0) for log in logging_outputs)
+        )
+
+        metrics.log_scalar(
+            "loss", loss_sum / sample_size / math.log(2), sample_size, round=3
+        )
+        metrics.log_scalar("ntokens", ntokens)
+        metrics.log_scalar("nsentences", nsentences)
+
+        correct = sum(log.get("correct", 0) for log in logging_outputs)
+        metrics.log_scalar("_correct", correct)
+
+        total = sum(log.get("count", 0) for log in logging_outputs)
+        metrics.log_scalar("_total", total)
+
+        if total > 0:
+            metrics.log_derived(
+                "accuracy",
+                lambda meters: safe_round(
+                    meters["_correct"].sum / meters["_total"].sum, 5
+                )
+                if meters["_total"].sum > 0
+                else float("nan"),
+            )
+
+        builtin_keys = {
+            "loss",
+            "ntokens",
+            "nsentences",
+            "sample_size",
+            "correct",
+            "count",
+        }
+
+        for k in logging_outputs[0]:
+            if k not in builtin_keys:
+                val = sum(log.get(k, 0) for log in logging_outputs) / len(
+                    logging_outputs
+                )
+                if k.startswith("loss"):
+                    metrics.log_scalar(k, val / sample_size / math.log(2), sample_size)
+                else:
+                    metrics.log_scalar(k, val, round=3)
+
+    @staticmethod
+    def logging_outputs_can_be_summed() -> bool:
+        """
+        Whether the logging outputs returned by `forward` can be summed
+        across workers prior to calling `reduce_metrics`. Setting this
+        to True will improves distributed training speed.
+        """
+        return False

fairseq/criterions/wav2vec_mtl.py

@@ -0,0 +1,137 @@
+import torch
+import math
+
+from fairseq import pdb
+from fairseq import utils, metrics
+from fairseq.criterions import LegacyFairseqCriterion, register_criterion
+from fairseq.criterions.wav2vec_criterion import Wav2vecCriterion
+from fairseq.criterions.ctc import CtcCriterion
+from fairseq.logging.meters import safe_round
+
+@register_criterion('wav2vec_mtl')
+class Wav2vecMTLCriterion(LegacyFairseqCriterion):
+
+    def __init__(self, args, task):
+        super().__init__(args, task)
+        self.mtlalpha = args.mtlalpha
+        self.w2v_criterion = Wav2vecCriterion(task, args.infonce, args.loss_weights, args.log_keys)
+        if self.mtlalpha > 0:
+            self.ctc_criterion = CtcCriterion(args, task)
+
+    @staticmethod
+    def add_args(parser):
+        Wav2vecCriterion.add_args(parser)
+        CtcCriterion.add_args(parser)
+        parser.add_argument('--mtlalpha', type=float, default=0.5)
+
+
+    def forward(self, model, sample, reduce=True):
+        net_output = model(**sample["net_input"])
+     
+        if self.mtlalpha > 0.0:
+            ctc_loss, ctc_sample_size, ctc_logging_output = self.ctc_criterion.get_loss(model, sample, net_output, reduce)
+        else:
+            ctc_loss = 0
+            ctc_sample_size = 0
+            ctc_logging_output = {}
+
+        infonce_loss, infonce_sample_size, infonce_logging_output = self.w2v_criterion.get_loss(model.w2v_encoder.w2v_model, sample, net_output['contrastive_res'], reduce)
+        loss = self.mtlalpha * ctc_loss + (1.0 - self.mtlalpha) * infonce_loss
+        sample_size = infonce_sample_size
+        logging_output = {'loss': loss, 'ntokens': ctc_logging_output['ntokens'], 'nsentences': ctc_logging_output['nsentences'],
+                           'ctc': ctc_logging_output, 'infonce': infonce_logging_output}
+
+        return loss, sample_size, logging_output
+
+    @staticmethod
+    def logging_outputs_can_be_summed() -> bool:
+        return False
+
+    @staticmethod
+    def reduce_metrics(logging_outputs) -> None:
+        loss_sum = utils.item(sum(log.get("loss", 0) for log in logging_outputs))
+
+        ctc_loss_sum = utils.item(sum(log['ctc'].get('loss', 0) for log in logging_outputs))
+        ctc_sample_size = utils.item(sum(log['ctc'].get('sample_size', 0) for log in logging_outputs))
+        ctc_ntokens = utils.item(sum(log['ctc'].get('ntokens', 0) for log in logging_outputs))
+        ctc_nsentences = utils.item(sum(log['ctc'].get('nsentences', 0) for log in logging_outputs))
+
+        ctras_loss_sum = utils.item(sum(log['infonce'].get('loss', 0) for log in logging_outputs)) 
+        ctras_sample_size = utils.item(sum(log['infonce'].get('sample_size', 0) for log in logging_outputs))
+        ctras_ntokens = utils.item(sum(log['infonce'].get('ntokens', 0) for log in logging_outputs))
+        ctras_nsentences = utils.item(sum(log['infonce'].get('nsentences', 0) for log in logging_outputs))
+
+        metrics.log_scalar(
+            "loss", loss_sum, 1, round=3)
+        metrics.log_scalar(
+            "ctc_loss", ctc_loss_sum / ctc_sample_size / math.log(2), ctc_sample_size, round=3
+        )
+        metrics.log_scalar(
+            "contrastive_loss", ctras_loss_sum / ctras_sample_size / math.log(2), ctras_sample_size, round=3
+        )
+        if ctc_sample_size != ctc_ntokens:
+            metrics.log_scalar(
+                "nll_loss", ctc_loss_sum / ctc_ntokens / math.log(2), ctc_ntokens, round=3
+            )
+        c_errors = sum(log['ctc'].get("c_errors", 0) for log in logging_outputs)
+        metrics.log_scalar("_c_errors", c_errors)
+        c_total = sum(log['ctc'].get("c_total", 0) for log in logging_outputs)
+        metrics.log_scalar("_c_total", c_total)
+        w_errors = sum(log['ctc'].get("w_errors", 0) for log in logging_outputs)
+        metrics.log_scalar("_w_errors", w_errors)
+        wv_errors = sum(log['ctc'].get("wv_errors", 0) for log in logging_outputs)
+        metrics.log_scalar("_wv_errors", wv_errors)
+        w_total = sum(log['ctc'].get("w_total", 0) for log in logging_outputs)
+        metrics.log_scalar("_w_total", w_total)
+
+        if c_total > 0:
+             metrics.log_derived(
+                "uer",
+                lambda meters: safe_round(meters["_c_errors"].sum * 100.0 / meters["_c_total"].sum, 3)
+                if meters["_c_total"].sum > 0
+                else float("nan"),
+            )
+        if w_total > 0:
+            metrics.log_derived(
+                "wer",
+                lambda meters: safe_round(meters["_w_errors"].sum * 100.0 / meters["_w_total"].sum, 3)
+                if meters["_w_total"].sum > 0
+                else float("nan"),
+            )
+            metrics.log_derived(
+                "raw_wer",
+                lambda meters: safe_round(meters["_wv_errors"].sum * 100.0 / meters["_w_total"].sum, 3)
+                if meters["_w_total"].sum > 0
+                else float("nan"),
+            )
+
+
+        metrics.log_scalar("nsentences", ctras_nsentences)
+        metrics.log_scalar("ctc_sample_size", ctc_sample_size)
+        metrics.log_scalar("contrastive_sample_size", ctras_sample_size)
+
+                
+        correct = sum(log['infonce'].get("correct", 0) for log in logging_outputs)
+        metrics.log_scalar("_correct", correct)
+  
+        total = sum(log['infonce'].get("count", 0) for log in logging_outputs)
+        metrics.log_scalar("_total", total)
+
+
+        if total > 0:
+            metrics.log_derived(
+                "accuracy",
+                lambda meters: safe_round(meters["_correct"].sum / meters["_total"].sum, 5)
+                if meters["_total"].sum > 0
+               else float("nan"),
+            )
+
+        builtin_keys = {'loss', 'ntokens', 'nsentences', 'sample_size', 'correct', 'count'}
+        for k in logging_outputs[0]['infonce']:
+            if k not in builtin_keys:
+                val = sum(log['infonce'].get(k, 0) for log in logging_outputs) / len(logging_outputs)
+                if k.startswith('loss'):
+                    metrics.log_scalar(k, val / ctras_sample_size / math.log(2), ctras_sample_size)
+                else:
+                    metrics.log_scalar(k, val, round=3)    
+

fairseq/data/__init__.py

@@ -0,0 +1,39 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+"""isort:skip_file"""
+
+from .dictionary import Dictionary, TruncatedDictionary
+
+from .fairseq_dataset import FairseqDataset, FairseqIterableDataset
+
+from .base_wrapper_dataset import BaseWrapperDataset
+
+from .add_target_dataset import AddTargetDataset
+from .audio.raw_audio_dataset import FileAudioDataset
+from .concat_dataset import ConcatDataset
+from .id_dataset import IdDataset
+from .resampling_dataset import ResamplingDataset
+
+from .iterators import (
+    CountingIterator,
+    EpochBatchIterator,
+    GroupedIterator,
+    ShardedIterator,
+)
+
+__all__ = [
+    "AddTargetDataset",
+    "ConcatDataset",
+    "CountingIterator",
+    "Dictionary",
+    "EpochBatchIterator",
+    "FairseqDataset",
+    "FairseqIterableDataset",
+    "FastaDataset",
+    "GroupedIterator",
+    "IdDataset",
+    "ResamplingDataset",
+    "ShardedIterator",
+]

fairseq/data/add_target_dataset.py

@@ -0,0 +1,70 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import torch
+
+from . import BaseWrapperDataset, data_utils
+
+
+class AddTargetDataset(BaseWrapperDataset):
+    def __init__(
+        self,
+        dataset,
+        labels,
+        pad,
+        eos,
+        batch_targets,
+        process_label=None,
+        add_to_input=False,
+    ):
+        super().__init__(dataset)
+        self.labels = labels
+        self.batch_targets = batch_targets
+        self.pad = pad
+        self.eos = eos
+        self.process_label = process_label
+        self.add_to_input = add_to_input
+
+    def get_label(self, index):
+        return (
+            self.labels[index]
+            if self.process_label is None
+            else self.process_label(self.labels[index])
+        )
+
+    def __getitem__(self, index):
+        item = self.dataset[index]
+        item["label"] = self.get_label(index)
+        return item
+
+    def size(self, index):
+        sz = self.dataset.size(index)
+        own_sz = len(self.get_label(index))
+        return (sz, own_sz)
+
+    def collater(self, samples):
+        collated = self.dataset.collater(samples)
+        if len(collated) == 0:
+            return collated
+        indices = set(collated["id"].tolist())
+        target = [s["label"] for s in samples if s["id"] in indices]
+
+        if self.batch_targets:
+            collated["target_lengths"] = torch.LongTensor([len(t) for t in target])
+            target = data_utils.collate_tokens(target, pad_idx=self.pad, left_pad=False)
+            collated["ntokens"] = collated["target_lengths"].sum().item()
+        else:
+            collated["ntokens"] = sum([len(t) for t in target])
+
+        collated["target"] = target
+
+        if self.add_to_input:
+            eos = target.new_full((target.size(0), 1), self.eos)
+            collated["target"] = torch.cat([target, eos], dim=-1).long()
+            collated["net_input"]["prev_output_tokens"] = torch.cat(
+                [eos, target], dim=-1
+            ).long()
+            collated["ntokens"] += target.size(0)
+        return collated

fairseq/data/audio/audio_utils.py

@@ -0,0 +1,85 @@
+import os.path as op
+from typing import BinaryIO, Optional, Tuple, Union
+
+import numpy as np
+
+
+def get_waveform(
+    path_or_fp: Union[str, BinaryIO], normalization=True
+) -> Tuple[np.ndarray, int]:
+    """Get the waveform and sample rate of a 16-bit mono-channel WAV or FLAC.
+
+    Args:
+        path_or_fp (str or BinaryIO): the path or file-like object
+        normalization (bool): Normalize values to [-1, 1] (Default: True)
+    """
+    if isinstance(path_or_fp, str):
+        ext = op.splitext(op.basename(path_or_fp))[1]
+        if ext not in {".flac", ".wav"}:
+            raise ValueError(f"Unsupported audio format: {ext}")
+
+    try:
+        import soundfile as sf
+    except ImportError:
+        raise ImportError("Please install soundfile to load WAV/FLAC file")
+
+    waveform, sample_rate = sf.read(path_or_fp, dtype="float32")
+    if not normalization:
+        waveform *= 2 ** 15  # denormalized to 16-bit signed integers
+    return waveform, sample_rate
+
+
+def _get_kaldi_fbank(waveform, sample_rate, n_bins=80) -> Optional[np.ndarray]:
+    """Get mel-filter bank features via PyKaldi."""
+    try:
+        from kaldi.feat.mel import MelBanksOptions
+        from kaldi.feat.fbank import FbankOptions, Fbank
+        from kaldi.feat.window import FrameExtractionOptions
+        from kaldi.matrix import Vector
+
+        mel_opts = MelBanksOptions()
+        mel_opts.num_bins = n_bins
+        frame_opts = FrameExtractionOptions()
+        frame_opts.samp_freq = sample_rate
+        opts = FbankOptions()
+        opts.mel_opts = mel_opts
+        opts.frame_opts = frame_opts
+        fbank = Fbank(opts=opts)
+        features = fbank.compute(Vector(waveform), 1.0).numpy()
+        return features
+    except ImportError:
+        return None
+
+
+def _get_torchaudio_fbank(waveform, sample_rate, n_bins=80) -> Optional[np.ndarray]:
+    """Get mel-filter bank features via TorchAudio."""
+    try:
+        import torch
+        import torchaudio.compliance.kaldi as ta_kaldi
+
+        waveform = torch.from_numpy(waveform).unsqueeze(0)
+        features = ta_kaldi.fbank(
+            waveform, num_mel_bins=n_bins, sample_frequency=sample_rate
+        )
+        return features.numpy()
+    except ImportError:
+        return None
+
+
+def get_fbank(path_or_fp: Union[str, BinaryIO], n_bins=80) -> np.ndarray:
+    """Get mel-filter bank features via PyKaldi or TorchAudio. Prefer PyKaldi
+    (faster CPP implementation) to TorchAudio (Python implementation). Note that
+    Kaldi/TorchAudio requires 16-bit signed integers as inputs and hence the
+    waveform should not be normalized."""
+    sound, sample_rate = get_waveform(path_or_fp, normalization=False)
+
+    features = _get_kaldi_fbank(sound, sample_rate, n_bins)
+    if features is None:
+        features = _get_torchaudio_fbank(sound, sample_rate, n_bins)
+    if features is None:
+        raise ImportError(
+            "Please install pyKaldi or torchaudio to enable "
+            "online filterbank feature extraction"
+        )
+
+    return features

fairseq/data/audio/feature_transforms/__init__.py

@@ -0,0 +1,82 @@
+import importlib
+import os
+from abc import ABC, abstractmethod
+from typing import Dict, Optional
+
+
+class AudioFeatureTransform(ABC):
+    @classmethod
+    @abstractmethod
+    def from_config_dict(cls, config: Optional[Dict] = None):
+        pass
+
+
+AUDIO_FEATURE_TRANSFORM_REGISTRY = {}
+AUDIO_FEATURE_TRANSFORM_CLASS_NAMES = set()
+
+
+def register_audio_feature_transform(name):
+    def register_audio_feature_transform_cls(cls):
+        if name in AUDIO_FEATURE_TRANSFORM_REGISTRY:
+            raise ValueError(f"Cannot register duplicate transform ({name})")
+        if not issubclass(cls, AudioFeatureTransform):
+            raise ValueError(
+                f"Transform ({name}: {cls.__name__}) must extend "
+                "AudioFeatureTransform"
+            )
+        if cls.__name__ in AUDIO_FEATURE_TRANSFORM_CLASS_NAMES:
+            raise ValueError(
+                f"Cannot register audio feature transform with duplicate "
+                f"class name ({cls.__name__})"
+            )
+        AUDIO_FEATURE_TRANSFORM_REGISTRY[name] = cls
+        AUDIO_FEATURE_TRANSFORM_CLASS_NAMES.add(cls.__name__)
+        return cls
+
+    return register_audio_feature_transform_cls
+
+
+def get_audio_feature_transform(name):
+    return AUDIO_FEATURE_TRANSFORM_REGISTRY[name]
+
+
+transforms_dir = os.path.dirname(__file__)
+for file in os.listdir(transforms_dir):
+    path = os.path.join(transforms_dir, file)
+    if (
+        not file.startswith("_")
+        and not file.startswith(".")
+        and (file.endswith(".py") or os.path.isdir(path))
+    ):
+        name = file[: file.find(".py")] if file.endswith(".py") else file
+        importlib.import_module("fairseq.data.audio.feature_transforms." + name)
+
+
+class CompositeAudioFeatureTransform(AudioFeatureTransform):
+    @classmethod
+    def from_config_dict(cls, config=None):
+        _config = {} if config is None else config
+        _transforms = _config.get("transforms")
+        if _transforms is None:
+            return None
+        transforms = [
+            get_audio_feature_transform(_t).from_config_dict(_config.get(_t))
+            for _t in _transforms
+        ]
+        return CompositeAudioFeatureTransform(transforms)
+
+    def __init__(self, transforms):
+        self.transforms = [t for t in transforms if t is not None]
+
+    def __call__(self, x):
+        for t in self.transforms:
+            x = t(x)
+        return x
+
+    def __repr__(self):
+        format_string = (
+            [self.__class__.__name__ + "("]
+            + [f"    {t.__repr__()}" for t in self.transforms]
+            + [")"]
+        )
+        return "\n".join(format_string)

fairseq/data/audio/feature_transforms/global_cmvn.py

@@ -0,0 +1,25 @@
+import numpy as np
+from fairseq.data.audio.feature_transforms import (
+    AudioFeatureTransform,
+    register_audio_feature_transform,
+)
+
+
+@register_audio_feature_transform("global_cmvn")
+class GlobalCMVN(AudioFeatureTransform):
+    """Global CMVN (cepstral mean and variance normalization). The global mean
+    and variance need to be pre-computed and stored in NumPy format (.npz)."""
+
+    @classmethod
+    def from_config_dict(cls, config=None):
+        _config = {} if config is None else config
+        return GlobalCMVN(_config.get("stats_npz_path"))
+
+    def __init__(self, stats_npz_path):
+        stats = np.load(stats_npz_path)
+        self.mean, self.std = stats["mean"], stats["std"]
+
+    def __call__(self, x):
+        x = np.subtract(x, self.mean)
+        x = np.divide(x, self.std)
+        return x

fairseq/data/audio/feature_transforms/specaugment.py

@@ -0,0 +1,131 @@
+import math
+import numbers
+from typing import Optional
+
+import numpy as np
+from fairseq.data.audio.feature_transforms import (
+    AudioFeatureTransform,
+    register_audio_feature_transform,
+)
+
+
+@register_audio_feature_transform("specaugment")
+class SpecAugmentTransform(AudioFeatureTransform):
+    """SpecAugment (https://arxiv.org/abs/1904.08779)"""
+
+    @classmethod
+    def from_config_dict(cls, config=None):
+        _config = {} if config is None else config
+        return SpecAugmentTransform(
+            _config.get("time_warp_W", 0),
+            _config.get("freq_mask_N", 0),
+            _config.get("freq_mask_F", 0),
+            _config.get("time_mask_N", 0),
+            _config.get("time_mask_T", 0),
+            _config.get("time_mask_p", 0.0),
+            _config.get("mask_value", None),
+        )
+
+    def __init__(
+        self,
+        time_warp_w: int = 0,
+        freq_mask_n: int = 0,
+        freq_mask_f: int = 0,
+        time_mask_n: int = 0,
+        time_mask_t: int = 0,
+        time_mask_p: float = 0.0,
+        mask_value: Optional[float] = 0.0,
+    ):
+        # Sanity checks
+        assert mask_value is None or isinstance(
+            mask_value, numbers.Number
+        ), f"mask_value (type: {type(mask_value)}) must be None or a number"
+        if freq_mask_n > 0:
+            assert freq_mask_f > 0, (
+                f"freq_mask_F ({freq_mask_f}) "
+                f"must be larger than 0 when doing freq masking."
+            )
+        if time_mask_n > 0:
+            assert time_mask_t > 0, (
+                f"time_mask_T ({time_mask_t}) must be larger than 0 when "
+                f"doing time masking."
+            )
+
+        self.time_warp_w = time_warp_w
+        self.freq_mask_n = freq_mask_n
+        self.freq_mask_f = freq_mask_f
+        self.time_mask_n = time_mask_n
+        self.time_mask_t = time_mask_t
+        self.time_mask_p = time_mask_p
+        self.mask_value = mask_value
+
+    def __repr__(self):
+        return (
+            self.__class__.__name__
+            + "("
+            + ", ".join(
+                [
+                    f"time_warp_w={self.time_warp_w}",
+                    f"freq_mask_n={self.freq_mask_n}",
+                    f"freq_mask_f={self.freq_mask_f}",
+                    f"time_mask_n={self.time_mask_n}",
+                    f"time_mask_t={self.time_mask_t}",
+                    f"time_mask_p={self.time_mask_p}",
+                ]
+            )
+            + ")"
+        )
+
+    def __call__(self, spectrogram):
+        assert len(spectrogram.shape) == 2, "spectrogram must be a 2-D tensor."
+
+        distorted = spectrogram.copy()  # make a copy of input spectrogram.
+        num_frames = spectrogram.shape[0]  # or 'tau' in the paper.
+        num_freqs = spectrogram.shape[1]  # or 'miu' in the paper.
+        mask_value = self.mask_value
+
+        if mask_value is None:  # if no value was specified, use local mean.
+            mask_value = spectrogram.mean()
+
+        if num_frames == 0:
+            return spectrogram
+
+        if num_freqs < self.freq_mask_f:
+            return spectrogram
+
+        if self.time_warp_w > 0:
+            if 2 * self.time_warp_w < num_frames:
+                import cv2
+
+                w0 = np.random.randint(self.time_warp_w, num_frames - self.time_warp_w)
+                w = np.random.randint(0, self.time_warp_w)
+                upper, lower = distorted[:w0, :], distorted[w0:, :]
+                upper = cv2.resize(
+                    upper, dsize=(num_freqs, w0 + w), interpolation=cv2.INTER_LINEAR
+                )
+                lower = cv2.resize(
+                    lower,
+                    dsize=(num_freqs, num_frames - w0 - w),
+                    interpolation=cv2.INTER_LINEAR,
+                )
+                distorted = np.concatenate((upper, lower), axis=0)
+
+        for _i in range(self.freq_mask_n):
+            f = np.random.randint(0, self.freq_mask_f)
+            f0 = np.random.randint(0, num_freqs - f)
+            if f != 0:
+                distorted[:, f0 : f0 + f] = mask_value
+
+        max_time_mask_t = min(
+            self.time_mask_t, math.floor(num_frames * self.time_mask_p)
+        )
+        if max_time_mask_t < 1:
+            return distorted
+
+        for _i in range(self.time_mask_n):
+            t = np.random.randint(0, max_time_mask_t)
+            t0 = np.random.randint(0, num_frames - t)
+            if t != 0:
+                distorted[t0 : t0 + t, :] = mask_value
+
+        return distorted

fairseq/data/audio/feature_transforms/utterance_cmvn.py

@@ -0,0 +1,40 @@
+import numpy as np
+from fairseq.data.audio.feature_transforms import (
+    AudioFeatureTransform,
+    register_audio_feature_transform,
+)
+
+
+@register_audio_feature_transform("utterance_cmvn")
+class UtteranceCMVN(AudioFeatureTransform):
+    """Utterance-level CMVN (cepstral mean and variance normalization)"""
+
+    @classmethod
+    def from_config_dict(cls, config=None):
+        _config = {} if config is None else config
+        return UtteranceCMVN(
+            _config.get("norm_means", True),
+            _config.get("norm_vars", True),
+        )
+
+    def __init__(self, norm_means=True, norm_vars=True):
+        self.norm_means, self.norm_vars = norm_means, norm_vars
+
+    def __repr__(self):
+        return (
+            self.__class__.__name__
+            + f"(norm_means={self.norm_means}, norm_vars={self.norm_vars})"
+        )
+
+    def __call__(self, x):
+        mean = x.mean(axis=0)
+        square_sums = (x ** 2).sum(axis=0)
+
+        if self.norm_means:
+            x = np.subtract(x, mean)
+        if self.norm_vars:
+            var = square_sums / x.shape[0] - mean ** 2
+            std = np.sqrt(np.maximum(var, 1e-10))
+            x = np.divide(x, std)
+
+        return x

fairseq/data/audio/raw_audio_dataset.py

@@ -0,0 +1,192 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+
+import logging
+import os
+import sys
+
+import numpy as np
+import torch
+import torch.nn.functional as F
+
+from .. import FairseqDataset
+
+
+logger = logging.getLogger(__name__)
+
+
+class RawAudioDataset(FairseqDataset):
+    def __init__(
+        self,
+        sample_rate,
+        max_sample_size=None,
+        min_sample_size=None,
+        shuffle=True,
+        min_length=0,
+        pad=False,
+        normalize=False,
+    ):
+        super().__init__()
+
+        self.sample_rate = sample_rate
+        self.sizes = []
+        self.max_sample_size = (
+            max_sample_size if max_sample_size is not None else sys.maxsize
+        )
+        self.min_sample_size = min_sample_size
+        self.min_length = min_length
+        self.pad = pad
+        self.shuffle = shuffle
+        self.normalize = normalize
+
+    def __getitem__(self, index):
+        raise NotImplementedError()
+
+    def __len__(self):
+        return len(self.sizes)
+
+    def postprocess(self, feats, curr_sample_rate):
+        if feats.dim() == 2:
+            feats = feats.mean(-1)
+
+        if curr_sample_rate != self.sample_rate:
+            raise Exception(f"sample rate: {curr_sample_rate}, need {self.sample_rate}")
+
+        assert feats.dim() == 1, feats.dim()
+
+        if self.normalize:
+            with torch.no_grad():
+                feats = F.layer_norm(feats, feats.shape)
+        return feats
+
+    def crop_to_max_size(self, wav, target_size):
+        size = len(wav)
+        diff = size - target_size
+        if diff <= 0:
+            return wav
+
+        start = np.random.randint(0, diff + 1)
+        end = size - diff + start
+        return wav[start:end]
+
+    def collater(self, samples):
+        samples = [s for s in samples if s["source"] is not None]
+        if len(samples) == 0:
+            return {}
+
+        sources = [s["source"] for s in samples]
+        sizes = [len(s) for s in sources]
+
+        if self.pad:
+            target_size = min(max(sizes), self.max_sample_size)
+        else:
+            target_size = min(min(sizes), self.max_sample_size)
+
+        collated_sources = sources[0].new_zeros(len(sources), target_size)
+        padding_mask = (
+            torch.BoolTensor(collated_sources.shape).fill_(False) if self.pad else None
+        )
+        for i, (source, size) in enumerate(zip(sources, sizes)):
+            diff = size - target_size
+            if diff == 0:
+                collated_sources[i] = source
+            elif diff < 0:
+                assert self.pad
+                collated_sources[i] = torch.cat(
+                    [source, source.new_full((-diff,), 0.0)]
+                )
+                padding_mask[i, diff:] = True
+            else:
+                collated_sources[i] = self.crop_to_max_size(source, target_size)
+
+        input = {"source": collated_sources}
+        if self.pad:
+            input["padding_mask"] = padding_mask
+        return {"id": torch.LongTensor([s["id"] for s in samples]), "net_input": input}
+
+    def num_tokens(self, index):
+        return self.size(index)
+
+    def size(self, index):
+        """Return an example's size as a float or tuple. This value is used when
+        filtering a dataset with ``--max-positions``."""
+        if self.pad:
+            return self.sizes[index]
+        return min(self.sizes[index], self.max_sample_size)
+
+    def ordered_indices(self):
+        """Return an ordered list of indices. Batches will be constructed based
+        on this order."""
+
+        if self.shuffle:
+            order = [np.random.permutation(len(self))]
+        else:
+            order = [np.arange(len(self))]
+
+        order.append(self.sizes)
+        return np.lexsort(order)[::-1]
+
+
+class FileAudioDataset(RawAudioDataset):
+    def __init__(
+        self,
+        manifest_path,
+        sample_rate,
+        max_sample_size=None,
+        min_sample_size=None,
+        shuffle=True,
+        min_length=0,
+        pad=False,
+        normalize=False,
+    ):
+        super().__init__(
+            sample_rate=sample_rate,
+            max_sample_size=max_sample_size,
+            min_sample_size=min_sample_size,
+            shuffle=shuffle,
+            min_length=min_length,
+            pad=pad,
+            normalize=normalize,
+        )
+
+        self.fnames = []
+        self.skipped = []
+
+        skipped = 0
+        count = 0
+        with open(manifest_path, "r") as f:
+            self.root_dir = f.readline().strip()
+            for line in f:
+                count += 1
+                items = line.strip().split("\t")
+                #assert len(items) == 2, line
+                sz = int(items[1])
+                if len(items) == 3:
+                    sr = int(items[2])
+                    assert sz % (sr / self.sample_rate) == 0
+                    sz = sz / (sr / self.sample_rate)
+                if min_length is not None and sz < min_length:
+                    skipped += 1
+                    self.skipped.append(count)
+                    continue
+                if pad and max_sample_size is not None and sz > max_sample_size:
+                    skipped += 1
+                    self.skipped.append(count)
+                    continue
+                self.fnames.append(items[0])
+                self.sizes.append(int(sz))
+        self.sizes = np.array(self.sizes)
+        logger.info(f"loaded {len(self.fnames)}, skipped {skipped} samples")
+
+    def __getitem__(self, index):
+        import soundfile as sf
+
+        fname = os.path.join(self.root_dir, self.fnames[index])
+        wav, curr_sample_rate = sf.read(fname)
+        #wav, curr_sample_rate = librosa.load(fname, sr=self.sample_rate)
+        feats = torch.from_numpy(wav).float()
+        feats = self.postprocess(feats, curr_sample_rate)
+        return {"id": index, "source": feats}

fairseq/data/audio/speech_to_text_dataset.py

@@ -0,0 +1,528 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import csv
+import io
+import logging
+import os.path as op
+import re
+from typing import Dict, List, Optional, Tuple
+
+import numpy as np
+import torch
+from fairseq.data import (
+    ConcatDataset,
+    Dictionary,
+    FairseqDataset,
+    ResamplingDataset,
+    data_utils as fairseq_data_utils,
+)
+from fairseq.data.audio.audio_utils import get_fbank, get_waveform
+from fairseq.data.audio.feature_transforms import CompositeAudioFeatureTransform
+
+
+logger = logging.getLogger(__name__)
+
+
+class S2TDataConfig(object):
+    """Wrapper class for data config YAML"""
+
+    def __init__(self, yaml_path):
+        try:
+            import yaml
+        except ImportError:
+            print("Please install PyYAML to load YAML files for " "S2T data config")
+        self.config = {}
+        if op.isfile(yaml_path):
+            try:
+                with open(yaml_path) as f:
+                    self.config = yaml.load(f, Loader=yaml.FullLoader)
+            except Exception as e:
+                logger.info(f"Failed to load config from {yaml_path}: {e}")
+        else:
+            logger.info(f"Cannot find {yaml_path}")
+
+    @property
+    def vocab_filename(self):
+        """fairseq vocabulary file under data root"""
+        return self.config.get("vocab_filename", "dict.txt")
+
+    @property
+    def shuffle(self) -> bool:
+        """Shuffle dataset samples before batching"""
+        return self.config.get("shuffle", False)
+
+    @property
+    def pre_tokenizer(self) -> Dict:
+        """Pre-tokenizer to apply before subword tokenization. Returning
+        a dictionary with `tokenizer` providing the tokenizer name and
+        the other items providing the tokenizer-specific arguments.
+        Tokenizers are defined in `fairseq.data.encoders.*`"""
+        return self.config.get("pre_tokenizer", {"tokenizer": None})
+
+    @property
+    def bpe_tokenizer(self) -> Dict:
+        """Subword tokenizer to apply after pre-tokenization. Returning
+        a dictionary with `bpe` providing the tokenizer name and
+        the other items providing the tokenizer-specific arguments.
+        Tokenizers are defined in `fairseq.data.encoders.*`"""
+        return self.config.get("bpe_tokenizer", {"bpe": None})
+
+    @property
+    def prepend_tgt_lang_tag(self) -> bool:
+        """Prepend target lang ID token as the target BOS (e.g. for to-many
+        multilingual setting). During inference, this requires `--prefix-size 1`
+        to force BOS to be lang ID token."""
+        return self.config.get("prepend_tgt_lang_tag", False)
+
+    @property
+    def input_feat_per_channel(self):
+        """The dimension of input features (per audio channel)"""
+        return self.config.get("input_feat_per_channel", 80)
+
+    @property
+    def input_channels(self):
+        """The number of channels in the input audio"""
+        return self.config.get("input_channels", 1)
+
+    @property
+    def sampling_alpha(self):
+        """Hyper-parameter alpha = 1/T for temperature-based resampling.
+        (alpha = 1 for no resampling)"""
+        return self.config.get("sampling_alpha", 1.0)
+
+    @property
+    def use_audio_input(self):
+        """Needed by the dataset loader to see if the model requires
+        raw audio as inputs."""
+        return self.config.get("use_audio_input", False)
+
+    @property
+    def audio_root(self):
+        """Audio paths in the manifest TSV can be relative and this provides
+        the root path. Set this to empty string when using absolute paths."""
+        return self.config.get("audio_root", "")
+
+    def get_feature_transforms(self, split, is_train):
+        """Split-specific feature transforms. Allowing train set wildcard `_train`,
+        evaluation set wildcard `_eval` and general wildcard `*` for matching."""
+        from copy import deepcopy
+
+        cfg = deepcopy(self.config)
+        _cur = cfg.get("transforms", {})
+        cur = _cur.get(split)
+        cur = _cur.get("_train") if cur is None and is_train else cur
+        cur = _cur.get("_eval") if cur is None and not is_train else cur
+        cur = _cur.get("*") if cur is None else cur
+        cfg["transforms"] = cur
+        return cfg
+
+
+def is_npy_data(data: bytes) -> bool:
+    return data[0] == 147 and data[1] == 78
+
+
+def is_flac_or_wav_data(data: bytes) -> bool:
+    is_flac = data[0] == 102 and data[1] == 76
+    is_wav = data[0] == 82 and data[1] == 73
+    return is_flac or is_wav
+
+
+def read_from_uncompressed_zip(file_path, offset, file_size) -> bytes:
+    with open(file_path, "rb") as f:
+        f.seek(offset)
+        data = f.read(file_size)
+    return data
+
+
+def get_features_from_npy_or_audio(path):
+    ext = op.splitext(op.basename(path))[1]
+    if ext not in {".npy", ".flac", ".wav"}:
+        raise ValueError(f'Unsupported file format for "{path}"')
+    return np.load(path) if ext == ".npy" else get_fbank(path)
+
+
+def get_features_or_waveform_from_uncompressed_zip(
+    path, byte_offset, byte_size, need_waveform=False
+):
+    assert path.endswith(".zip")
+    data = read_from_uncompressed_zip(path, byte_offset, byte_size)
+    f = io.BytesIO(data)
+    if is_npy_data(data):
+        features_or_waveform = np.load(f)
+    elif is_flac_or_wav_data(data):
+        features_or_waveform = get_waveform(f)[0] if need_waveform else get_fbank(f)
+    else:
+        raise ValueError(f'Unknown file format for "{path}"')
+    return features_or_waveform
+
+
+def get_features_or_waveform(path: str, need_waveform=False):
+    """Get speech features from .npy file or waveform from .wav/.flac file.
+    The file may be inside an uncompressed ZIP file and is accessed via byte
+    offset and length.
+
+    Args:
+        path (str): File path in the format of "<.npy/.wav/.flac path>" or
+        "<zip path>:<byte offset>:<byte length>".
+        need_waveform (bool): return waveform instead of features.
+
+    Returns:
+        features_or_waveform (numpy.ndarray): speech features or waveform.
+    """
+    _path, *extra = path.split(":")
+    if not op.exists(_path):
+        raise FileNotFoundError(f"File not found: {_path}")
+
+    if len(extra) == 0:
+        if need_waveform:
+            return get_waveform(_path)
+        return get_features_from_npy_or_audio(_path)
+    elif len(extra) == 2:
+        extra = [int(i) for i in extra]
+        features_or_waveform = get_features_or_waveform_from_uncompressed_zip(
+            _path, extra[0], extra[1], need_waveform=need_waveform
+        )
+    else:
+        raise ValueError(f"Invalid path: {path}")
+
+    return features_or_waveform
+
+
+def _collate_frames(
+    frames: List[torch.Tensor], is_audio_input: bool = False
+) -> torch.Tensor:
+    """
+    Convert a list of 2D frames into a padded 3D tensor
+    Args:
+        frames (list): list of 2D frames of size L[i]*f_dim. Where L[i] is
+            length of i-th frame and f_dim is static dimension of features
+    Returns:
+        3D tensor of size len(frames)*len_max*f_dim where len_max is max of L[i]
+    """
+    max_len = max(frame.size(0) for frame in frames)
+    if is_audio_input:
+        out = frames[0].new_zeros((len(frames), max_len))
+    else:
+        out = frames[0].new_zeros((len(frames), max_len, frames[0].size(1)))
+    for i, v in enumerate(frames):
+        out[i, : v.size(0)] = v
+    return out
+
+
+class SpeechToTextDataset(FairseqDataset):
+    LANG_TAG_TEMPLATE = "<lang:{}>"
+
+    def __init__(
+        self,
+        split: str,
+        is_train_split: bool,
+        data_cfg: S2TDataConfig,
+        audio_paths: List[str],
+        n_frames: List[int],
+        src_texts: Optional[List[str]] = None,
+        tgt_texts: Optional[List[str]] = None,
+        speakers: Optional[List[str]] = None,
+        src_langs: Optional[List[str]] = None,
+        tgt_langs: Optional[List[str]] = None,
+        ids: Optional[List[str]] = None,
+        tgt_dict: Optional[Dictionary] = None,
+        pre_tokenizer=None,
+        bpe_tokenizer=None,
+    ):
+        self.split, self.is_train_split = split, is_train_split
+        self.data_cfg = data_cfg
+        self.audio_paths, self.n_frames = audio_paths, n_frames
+        self.n_samples = len(audio_paths)
+        assert len(n_frames) == self.n_samples > 0
+        assert src_texts is None or len(src_texts) == self.n_samples
+        assert tgt_texts is None or len(tgt_texts) == self.n_samples
+        assert speakers is None or len(speakers) == self.n_samples
+        assert src_langs is None or len(src_langs) == self.n_samples
+        assert tgt_langs is None or len(tgt_langs) == self.n_samples
+        assert ids is None or len(ids) == self.n_samples
+        assert (tgt_dict is None and tgt_texts is None) or (
+            tgt_dict is not None and tgt_texts is not None
+        )
+        self.src_texts, self.tgt_texts = src_texts, tgt_texts
+        self.src_langs, self.tgt_langs = src_langs, tgt_langs
+        self.tgt_dict = tgt_dict
+        self.check_tgt_lang_tag()
+        self.ids = ids
+        self.shuffle = data_cfg.shuffle if is_train_split else False
+
+        self.feature_transforms = CompositeAudioFeatureTransform.from_config_dict(
+            self.data_cfg.get_feature_transforms(split, is_train_split)
+        )
+
+        self.pre_tokenizer = pre_tokenizer
+        self.bpe_tokenizer = bpe_tokenizer
+
+        logger.info(self.__repr__())
+
+    def __repr__(self):
+        return (
+            self.__class__.__name__
+            + f'(split="{self.split}", n_samples={self.n_samples}, '
+            f"prepend_tgt_lang_tag={self.data_cfg.prepend_tgt_lang_tag}, "
+            f"shuffle={self.shuffle}, transforms={self.feature_transforms})"
+        )
+
+    @classmethod
+    def is_lang_tag(cls, token):
+        pattern = cls.LANG_TAG_TEMPLATE.replace("{}", "(.*)")
+        return re.match(pattern, token)
+
+    def check_tgt_lang_tag(self):
+        if self.data_cfg.prepend_tgt_lang_tag:
+            assert self.tgt_langs is not None and self.tgt_dict is not None
+            tgt_lang_tags = [
+                self.LANG_TAG_TEMPLATE.format(t) for t in set(self.tgt_langs)
+            ]
+            assert all(t in self.tgt_dict for t in tgt_lang_tags)
+
+    def tokenize_text(self, text: str):
+        if self.pre_tokenizer is not None:
+            text = self.pre_tokenizer.encode(text)
+        if self.bpe_tokenizer is not None:
+            text = self.bpe_tokenizer.encode(text)
+        return text
+
+    def __getitem__(
+        self, index: int
+    ) -> Tuple[int, torch.Tensor, Optional[torch.Tensor]]:
+        source = get_features_or_waveform(
+            self.audio_paths[index], need_waveform=self.data_cfg.use_audio_input
+        )
+        if self.feature_transforms is not None:
+            assert not self.data_cfg.use_audio_input
+            source = self.feature_transforms(source)
+        source = torch.from_numpy(source).float()
+
+        target = None
+        if self.tgt_texts is not None:
+            tokenized = self.tokenize_text(self.tgt_texts[index])
+            target = self.tgt_dict.encode_line(
+                tokenized, add_if_not_exist=False, append_eos=True
+            ).long()
+            if self.data_cfg.prepend_tgt_lang_tag:
+                lang_tag = self.LANG_TAG_TEMPLATE.format(self.tgt_langs[index])
+                lang_tag_idx = self.tgt_dict.index(lang_tag)
+                target = torch.cat((torch.LongTensor([lang_tag_idx]), target), 0)
+        return index, source, target
+
+    def __len__(self):
+        return self.n_samples
+
+    def collater(self, samples: List[Tuple[int, torch.Tensor, torch.Tensor]]) -> Dict:
+        if len(samples) == 0:
+            return {}
+        indices = torch.tensor([i for i, _, _ in samples], dtype=torch.long)
+        frames = _collate_frames(
+            [s for _, s, _ in samples], self.data_cfg.use_audio_input
+        )
+        # sort samples by descending number of frames
+        n_frames = torch.tensor([s.size(0) for _, s, _ in samples], dtype=torch.long)
+        n_frames, order = n_frames.sort(descending=True)
+        indices = indices.index_select(0, order)
+        frames = frames.index_select(0, order)
+
+        target, target_lengths = None, None
+        prev_output_tokens = None
+        ntokens = None
+        if self.tgt_texts is not None:
+            target = fairseq_data_utils.collate_tokens(
+                [t for _, _, t in samples],
+                self.tgt_dict.pad(),
+                self.tgt_dict.eos(),
+                left_pad=False,
+                move_eos_to_beginning=False,
+            )
+            target = target.index_select(0, order)
+            target_lengths = torch.tensor(
+                [t.size(0) for _, _, t in samples], dtype=torch.long
+            ).index_select(0, order)
+            prev_output_tokens = fairseq_data_utils.collate_tokens(
+                [t for _, _, t in samples],
+                self.tgt_dict.pad(),
+                self.tgt_dict.eos(),
+                left_pad=False,
+                move_eos_to_beginning=True,
+            )
+            prev_output_tokens = prev_output_tokens.index_select(0, order)
+            ntokens = sum(t.size(0) for _, _, t in samples)
+
+        out = {
+            "id": indices,
+            "net_input": {
+                "src_tokens": frames,
+                "src_lengths": n_frames,
+                "prev_output_tokens": prev_output_tokens,
+            },
+            "target": target,
+            "target_lengths": target_lengths,
+            "ntokens": ntokens,
+            "nsentences": len(samples),
+        }
+        return out
+
+    def num_tokens(self, index):
+        return self.n_frames[index]
+
+    def size(self, index):
+        t_len = 0
+        if self.tgt_texts is not None:
+            tokenized = self.tokenize_text(self.tgt_texts[index])
+            t_len = len(tokenized.split(" "))
+        return self.n_frames[index], t_len
+
+    @property
+    def sizes(self):
+        return np.array(self.n_frames)
+
+    @property
+    def can_reuse_epoch_itr_across_epochs(self):
+        return True
+
+    def ordered_indices(self):
+        if self.shuffle:
+            order = [np.random.permutation(len(self))]
+        else:
+            order = [np.arange(len(self))]
+        # first by descending order of # of frames then by original/random order
+        order.append([-n for n in self.n_frames])
+        return np.lexsort(order)
+
+    def prefetch(self, indices):
+        raise False
+
+
+class SpeechToTextDatasetCreator(object):
+    # mandatory columns
+    KEY_ID, KEY_AUDIO, KEY_N_FRAMES = "id", "audio", "n_frames"
+    KEY_TGT_TEXT = "tgt_text"
+    # optional columns
+    KEY_SPEAKER, KEY_SRC_TEXT = "speaker", "src_text"
+    KEY_SRC_LANG, KEY_TGT_LANG = "src_lang", "tgt_lang"
+    # default values
+    DEFAULT_SPEAKER = DEFAULT_SRC_TEXT = DEFAULT_LANG = ""
+
+    @classmethod
+    def _from_list(
+        cls,
+        split_name: str,
+        is_train_split,
+        samples: List[List[Dict]],
+        data_cfg: S2TDataConfig,
+        tgt_dict,
+        pre_tokenizer,
+        bpe_tokenizer,
+    ) -> SpeechToTextDataset:
+        audio_paths, n_frames, src_texts, tgt_texts, ids = [], [], [], [], []
+        speakers, src_langs, tgt_langs = [], [], []
+        for s in samples:
+            ids.extend([ss[cls.KEY_ID] for ss in s])
+            audio_paths.extend(
+                [op.join(data_cfg.audio_root, ss[cls.KEY_AUDIO]) for ss in s]
+            )
+            n_frames.extend([int(ss[cls.KEY_N_FRAMES]) for ss in s])
+            tgt_texts.extend([ss[cls.KEY_TGT_TEXT] for ss in s])
+            src_texts.extend(
+                [ss.get(cls.KEY_SRC_TEXT, cls.DEFAULT_SRC_TEXT) for ss in s]
+            )
+            speakers.extend([ss.get(cls.KEY_SPEAKER, cls.DEFAULT_SPEAKER) for ss in s])
+            src_langs.extend([ss.get(cls.KEY_SRC_LANG, cls.DEFAULT_LANG) for ss in s])
+            tgt_langs.extend([ss.get(cls.KEY_TGT_LANG, cls.DEFAULT_LANG) for ss in s])
+        return SpeechToTextDataset(
+            split_name,
+            is_train_split,
+            data_cfg,
+            audio_paths,
+            n_frames,
+            src_texts,
+            tgt_texts,
+            speakers,
+            src_langs,
+            tgt_langs,
+            ids,
+            tgt_dict,
+            pre_tokenizer,
+            bpe_tokenizer,
+        )
+
+    @classmethod
+    def _get_size_ratios(cls, ids: List[str], sizes: List[int], alpha: float = 1.0):
+        """Size ratios for temperature-based sampling
+        (https://arxiv.org/abs/1907.05019)"""
+        _sizes = np.array(sizes)
+        prob = _sizes / _sizes.sum()
+        smoothed_prob = prob ** alpha
+        smoothed_prob = smoothed_prob / smoothed_prob.sum()
+        size_ratio = (smoothed_prob * _sizes.sum()) / _sizes
+
+        o_str = str({_i: f"{prob[i]:.3f}" for i, _i in enumerate(ids)})
+        logger.info(f"original sampling probability: {o_str}")
+        p_str = str({_i: f"{smoothed_prob[i]:.3f}" for i, _i in enumerate(ids)})
+        logger.info(f"balanced sampling probability: {p_str}")
+        sr_str = str({_id: f"{size_ratio[i]:.3f}" for i, _id in enumerate(ids)})
+        logger.info(f"balanced sampling size ratio: {sr_str}")
+        return size_ratio.tolist()
+
+    @classmethod
+    def from_tsv(
+        cls,
+        root: str,
+        data_cfg: S2TDataConfig,
+        splits: str,
+        tgt_dict,
+        pre_tokenizer,
+        bpe_tokenizer,
+        is_train_split: bool,
+        epoch: int,
+        seed: int,
+    ) -> SpeechToTextDataset:
+        samples = []
+        _splits = splits.split(",")
+        for split in _splits:
+            tsv_path = op.join(root, f"{split}.tsv")
+            if not op.isfile(tsv_path):
+                raise FileNotFoundError(f"Dataset not found: {tsv_path}")
+            with open(tsv_path) as f:
+                reader = csv.DictReader(
+                    f,
+                    delimiter="\t",
+                    quotechar=None,
+                    doublequote=False,
+                    lineterminator="\n",
+                    quoting=csv.QUOTE_NONE,
+                )
+                samples.append([dict(e) for e in reader])
+                assert len(samples) > 0
+
+        datasets = [
+            cls._from_list(
+                name,
+                is_train_split,
+                [s],
+                data_cfg,
+                tgt_dict,
+                pre_tokenizer,
+                bpe_tokenizer,
+            )
+            for name, s in zip(_splits, samples)
+        ]
+
+        if is_train_split and len(_splits) > 1 and data_cfg.sampling_alpha != 1.0:
+            # temperature-based sampling
+            size_ratios = cls._get_size_ratios(
+                _splits, [len(s) for s in samples], alpha=data_cfg.sampling_alpha
+            )
+            datasets = [
+                ResamplingDataset(
+                    d, size_ratio=r, seed=seed, epoch=epoch, replace=(r >= 1.0)
+                )
+                for d, r in zip(datasets, size_ratios)
+            ]
+        return ConcatDataset(datasets)

fairseq/data/base_wrapper_dataset.py

@@ -0,0 +1,78 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from torch.utils.data.dataloader import default_collate
+
+from . import FairseqDataset
+
+
+class BaseWrapperDataset(FairseqDataset):
+    def __init__(self, dataset):
+        super().__init__()
+        self.dataset = dataset
+
+    def __getitem__(self, index):
+        return self.dataset[index]
+
+    def __len__(self):
+        return len(self.dataset)
+
+    def collater(self, samples):
+        if hasattr(self.dataset, "collater"):
+            return self.dataset.collater(samples)
+        else:
+            return default_collate(samples)
+
+    @property
+    def sizes(self):
+        return self.dataset.sizes
+
+    def num_tokens(self, index):
+        return self.dataset.num_tokens(index)
+
+    def size(self, index):
+        return self.dataset.size(index)
+
+    def ordered_indices(self):
+        return self.dataset.ordered_indices()
+
+    @property
+    def supports_prefetch(self):
+        return getattr(self.dataset, "supports_prefetch", False)
+
+    def attr(self, attr: str, index: int):
+        return self.dataset.attr(attr, index)
+
+    def prefetch(self, indices):
+        self.dataset.prefetch(indices)
+
+    def get_batch_shapes(self):
+        return self.dataset.get_batch_shapes()
+
+    def batch_by_size(
+        self,
+        indices,
+        max_tokens=None,
+        max_sentences=None,
+        required_batch_size_multiple=1,
+    ):
+        return self.dataset.batch_by_size(
+            indices,
+            max_tokens=max_tokens,
+            max_sentences=max_sentences,
+            required_batch_size_multiple=required_batch_size_multiple,
+        )
+
+    def filter_indices_by_size(self, indices, max_sizes):
+        return self.dataset.filter_indices_by_size(indices, max_sizes)
+
+    @property
+    def can_reuse_epoch_itr_across_epochs(self):
+        return self.dataset.can_reuse_epoch_itr_across_epochs
+
+    def set_epoch(self, epoch):
+        super().set_epoch(epoch)
+        if hasattr(self.dataset, "set_epoch"):
+            self.dataset.set_epoch(epoch)

fairseq/data/concat_dataset.py

@@ -0,0 +1,124 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import bisect
+
+import numpy as np
+from torch.utils.data.dataloader import default_collate
+
+from . import FairseqDataset
+
+
+class ConcatDataset(FairseqDataset):
+    @staticmethod
+    def cumsum(sequence, sample_ratios):
+        r, s = [], 0
+        for e, ratio in zip(sequence, sample_ratios):
+            curr_len = int(ratio * len(e))
+            r.append(curr_len + s)
+            s += curr_len
+        return r
+
+    def __init__(self, datasets, sample_ratios=1):
+        super(ConcatDataset, self).__init__()
+        assert len(datasets) > 0, "datasets should not be an empty iterable"
+        self.datasets = list(datasets)
+        if isinstance(sample_ratios, int):
+            sample_ratios = [sample_ratios] * len(self.datasets)
+        self.sample_ratios = sample_ratios
+        self.cumulative_sizes = self.cumsum(self.datasets, sample_ratios)
+        self.real_sizes = [len(d) for d in self.datasets]
+
+    def __len__(self):
+        return self.cumulative_sizes[-1]
+
+    def __getitem__(self, idx):
+        dataset_idx, sample_idx = self._get_dataset_and_sample_index(idx)
+        return self.datasets[dataset_idx][sample_idx]
+
+    def _get_dataset_and_sample_index(self, idx: int):
+        dataset_idx = bisect.bisect_right(self.cumulative_sizes, idx)
+        if dataset_idx == 0:
+            sample_idx = idx
+        else:
+            sample_idx = idx - self.cumulative_sizes[dataset_idx - 1]
+        sample_idx = sample_idx % self.real_sizes[dataset_idx]
+        return dataset_idx, sample_idx
+
+    def collater(self, samples, **extra_args):
+        # For now only supports datasets with same underlying collater implementations
+        if hasattr(self.datasets[0], "collater"):
+            return self.datasets[0].collater(samples, **extra_args)
+        else:
+            return default_collate(samples, **extra_args)
+
+    def size(self, idx: int):
+        """
+        Return an example's size as a float or tuple.
+        """
+        dataset_idx, sample_idx = self._get_dataset_and_sample_index(idx)
+        return self.datasets[dataset_idx].size(sample_idx)
+
+    def num_tokens(self, index: int):
+        return np.max(self.size(index))
+
+    def attr(self, attr: str, index: int):
+        dataset_idx = bisect.bisect_right(self.cumulative_sizes, index)
+        return getattr(self.datasets[dataset_idx], attr, None)
+
+    @property
+    def sizes(self):
+        _dataset_sizes = []
+        for ds, sr in zip(self.datasets, self.sample_ratios):
+            if isinstance(ds.sizes, np.ndarray):
+                _dataset_sizes.append(np.tile(ds.sizes, sr))
+            else:
+                # Only support underlying dataset with single size array.
+                assert isinstance(ds.sizes, list)
+                _dataset_sizes.append(np.tile(ds.sizes[0], sr))
+        return np.concatenate(_dataset_sizes)
+
+    @property
+    def supports_prefetch(self):
+        return all(d.supports_prefetch for d in self.datasets)
+
+    def ordered_indices(self):
+        """
+        Returns indices sorted by length. So less padding is needed.
+        """
+        if isinstance(self.sizes, np.ndarray) and len(self.sizes.shape) > 1:
+            # special handling for concatenating lang_pair_datasets
+            indices = np.arange(len(self))
+            sizes = self.sizes
+            tgt_sizes = (
+                sizes[:, 1] if len(sizes.shape) > 0 and sizes.shape[1] > 1 else None
+            )
+            src_sizes = (
+                sizes[:, 0] if len(sizes.shape) > 0 and sizes.shape[1] > 1 else sizes
+            )
+            # sort by target length, then source length
+            if tgt_sizes is not None:
+                indices = indices[np.argsort(tgt_sizes[indices], kind="mergesort")]
+            return indices[np.argsort(src_sizes[indices], kind="mergesort")]
+        else:
+            return np.argsort(self.sizes)
+
+    def prefetch(self, indices):
+        frm = 0
+        for to, ds in zip(self.cumulative_sizes, self.datasets):
+            real_size = len(ds)
+            if getattr(ds, "supports_prefetch", False):
+                ds.prefetch([(i - frm) % real_size for i in indices if frm <= i < to])
+            frm = to
+
+    @property
+    def can_reuse_epoch_itr_across_epochs(self):
+        return all(d.can_reuse_epoch_itr_across_epochs for d in self.datasets)
+
+    def set_epoch(self, epoch):
+        super().set_epoch(epoch)
+        for ds in self.datasets:
+            if hasattr(ds, "set_epoch"):
+                ds.set_epoch(epoch)

fairseq/data/concat_sentences_dataset.py

@@ -0,0 +1,54 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import torch
+
+from . import FairseqDataset
+
+
+class ConcatSentencesDataset(FairseqDataset):
+    def __init__(self, *datasets):
+        super().__init__()
+        self.datasets = datasets
+        assert all(
+            len(ds) == len(datasets[0]) for ds in datasets
+        ), "datasets must have the same length"
+
+    def __getitem__(self, index):
+        return torch.cat([ds[index] for ds in self.datasets])
+
+    def __len__(self):
+        return len(self.datasets[0])
+
+    def collater(self, samples):
+        return self.datasets[0].collater(samples)
+
+    @property
+    def sizes(self):
+        return sum(ds.sizes for ds in self.datasets)
+
+    def num_tokens(self, index):
+        return sum(ds.num_tokens(index) for ds in self.datasets)
+
+    def size(self, index):
+        return sum(ds.size(index) for ds in self.datasets)
+
+    def ordered_indices(self):
+        return self.datasets[0].ordered_indices()
+
+    @property
+    def supports_prefetch(self):
+        return any(getattr(ds, "supports_prefetch", False) for ds in self.datasets)
+
+    def prefetch(self, indices):
+        for ds in self.datasets:
+            if getattr(ds, "supports_prefetch", False):
+                ds.prefetch(indices)
+
+    def set_epoch(self, epoch):
+        super().set_epoch(epoch)
+        for ds in self.datasets:
+            if hasattr(ds, "set_epoch"):
+                ds.set_epoch(epoch)

fairseq/data/data_utils.py

@@ -0,0 +1,499 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+try:
+    from collections.abc import Iterable
+except ImportError:
+    from collections import Iterable
+import contextlib
+import itertools
+import logging
+import os
+import warnings
+from typing import Optional, Tuple
+
+import numpy as np
+import torch
+
+
+logger = logging.getLogger(__name__)
+
+
+def infer_language_pair(path):
+    """Infer language pair from filename: <split>.<lang1>-<lang2>.(...).idx"""
+    src, dst = None, None
+    for filename in os.listdir(path):
+        parts = filename.split(".")
+        if len(parts) >= 3 and len(parts[1].split("-")) == 2:
+            return parts[1].split("-")
+    return src, dst
+
+
+def collate_tokens(
+    values,
+    pad_idx,
+    eos_idx=None,
+    left_pad=False,
+    move_eos_to_beginning=False,
+    pad_to_length=None,
+    pad_to_multiple=1,
+):
+    """Convert a list of 1d tensors into a padded 2d tensor."""
+    size = max(v.size(0) for v in values)
+    size = size if pad_to_length is None else max(size, pad_to_length)
+    if pad_to_multiple != 1 and size % pad_to_multiple != 0:
+        size = int(((size - 0.1) // pad_to_multiple + 1) * pad_to_multiple)
+    res = values[0].new(len(values), size).fill_(pad_idx)
+
+    def copy_tensor(src, dst):
+        assert dst.numel() == src.numel()
+        if move_eos_to_beginning:
+            if eos_idx is None:
+                # if no eos_idx is specified, then use the last token in src
+                dst[0] = src[-1]
+            else:
+                dst[0] = eos_idx
+            dst[1:] = src[:-1]
+        else:
+            dst.copy_(src)
+
+    for i, v in enumerate(values):
+        copy_tensor(v, res[i][size - len(v) :] if left_pad else res[i][: len(v)])
+    return res
+
+
+def load_indexed_dataset(
+    path, dictionary=None, dataset_impl=None, combine=False, default="cached"
+):
+    """A helper function for loading indexed datasets.
+
+    Args:
+        path (str): path to indexed dataset (e.g., 'data-bin/train')
+        dictionary (~fairseq.data.Dictionary): data dictionary
+        dataset_impl (str, optional): which dataset implementation to use. If
+            not provided, it will be inferred automatically. For legacy indexed
+            data we use the 'cached' implementation by default.
+        combine (bool, optional): automatically load and combine multiple
+            datasets. For example, if *path* is 'data-bin/train', then we will
+            combine 'data-bin/train', 'data-bin/train1', ... and return a
+            single ConcatDataset instance.
+    """
+    from fairseq.data.concat_dataset import ConcatDataset
+    import fairseq.data.indexed_dataset as indexed_dataset
+
+    datasets = []
+    for k in itertools.count():
+        path_k = path + (str(k) if k > 0 else "")
+        path_k = indexed_dataset.get_indexed_dataset_to_local(path_k)
+
+        dataset_impl_k = dataset_impl
+        if dataset_impl_k is None:
+            dataset_impl_k = indexed_dataset.infer_dataset_impl(path_k)
+        dataset = indexed_dataset.make_dataset(
+            path_k,
+            impl=dataset_impl_k or default,
+            fix_lua_indexing=True,
+            dictionary=dictionary,
+        )
+        if dataset is None:
+            break
+        logger.info("loaded {} examples from: {}".format(len(dataset), path_k))
+        datasets.append(dataset)
+        if not combine:
+            break
+    if len(datasets) == 0:
+        return None
+    elif len(datasets) == 1:
+        return datasets[0]
+    else:
+        return ConcatDataset(datasets)
+
+
+@contextlib.contextmanager
+def numpy_seed(seed, *addl_seeds):
+    """Context manager which seeds the NumPy PRNG with the specified seed and
+    restores the state afterward"""
+    if seed is None:
+        yield
+        return
+    if len(addl_seeds) > 0:
+        seed = int(hash((seed, *addl_seeds)) % 1e6)
+    state = np.random.get_state()
+    np.random.seed(seed)
+    try:
+        yield
+    finally:
+        np.random.set_state(state)
+
+
+def collect_filtered(function, iterable, filtered):
+    """
+    Similar to :func:`filter` but collects filtered elements in ``filtered``.
+
+    Args:
+        function (callable): function that returns ``False`` for elements that
+            should be filtered
+        iterable (iterable): iterable to filter
+        filtered (list): list to store filtered elements
+    """
+    for el in iterable:
+        if function(el):
+            yield el
+        else:
+            filtered.append(el)
+
+
+def _filter_by_size_dynamic(indices, size_fn, max_positions, raise_exception=False):
+    def compare_leq(a, b):
+        return a <= b if not isinstance(a, tuple) else max(a) <= b
+
+    def check_size(idx):
+        if isinstance(max_positions, float) or isinstance(max_positions, int):
+            return size_fn(idx) <= max_positions
+        elif isinstance(max_positions, dict):
+            idx_size = size_fn(idx)
+            assert isinstance(idx_size, dict)
+            intersect_keys = set(max_positions.keys()) & set(idx_size.keys())
+            return all(
+                all(
+                    a is None or b is None or a <= b
+                    for a, b in zip(idx_size[key], max_positions[key])
+                )
+                for key in intersect_keys
+            )
+        else:
+            # Hacky as heck, for the specific case of multilingual training with RoundRobin.
+            if isinstance(size_fn(idx), dict) and isinstance(max_positions, tuple):
+                return all(
+                    a is None or b is None or compare_leq(a, b)
+                    for a, b in zip(size_fn(idx).values(), max_positions)
+                )
+            # For MultiCorpusSampledDataset, will generalize it later
+            if not isinstance(size_fn(idx), Iterable):
+                return all(size_fn(idx) <= b for b in max_positions)
+            return all(
+                a is None or b is None or a <= b
+                for a, b in zip(size_fn(idx), max_positions)
+            )
+
+    ignored = []
+    itr = collect_filtered(check_size, indices, ignored)
+    indices = np.fromiter(itr, dtype=np.int64, count=-1)
+    return indices, ignored
+
+
+def filter_by_size(indices, dataset, max_positions, raise_exception=False):
+    """
+    [deprecated] Filter indices based on their size.
+    Use `FairseqDataset::filter_indices_by_size` instead.
+
+    Args:
+        indices (List[int]): ordered list of dataset indices
+        dataset (FairseqDataset): fairseq dataset instance
+        max_positions (tuple): filter elements larger than this size.
+            Comparisons are done component-wise.
+        raise_exception (bool, optional): if ``True``, raise an exception if
+            any elements are filtered (default: False).
+    """
+    warnings.warn(
+        "data_utils.filter_by_size is deprecated. "
+        "Use `FairseqDataset::filter_indices_by_size` instead.",
+        stacklevel=2,
+    )
+    if isinstance(max_positions, float) or isinstance(max_positions, int):
+        if hasattr(dataset, "sizes") and isinstance(dataset.sizes, np.ndarray):
+            ignored = indices[dataset.sizes[indices] > max_positions].tolist()
+            indices = indices[dataset.sizes[indices] <= max_positions]
+        elif (
+            hasattr(dataset, "sizes")
+            and isinstance(dataset.sizes, list)
+            and len(dataset.sizes) == 1
+        ):
+            ignored = indices[dataset.sizes[0][indices] > max_positions].tolist()
+            indices = indices[dataset.sizes[0][indices] <= max_positions]
+        else:
+            indices, ignored = _filter_by_size_dynamic(
+                indices, dataset.size, max_positions
+            )
+    else:
+        indices, ignored = _filter_by_size_dynamic(indices, dataset.size, max_positions)
+
+    if len(ignored) > 0 and raise_exception:
+        raise Exception(
+            (
+                "Size of sample #{} is invalid (={}) since max_positions={}, "
+                "skip this example with --skip-invalid-size-inputs-valid-test"
+            ).format(ignored[0], dataset.size(ignored[0]), max_positions)
+        )
+    if len(ignored) > 0:
+        logger.warning(
+            (
+                "{} samples have invalid sizes and will be skipped, "
+                "max_positions={}, first few sample ids={}"
+            ).format(len(ignored), max_positions, ignored[:10])
+        )
+    return indices
+
+
+def filter_paired_dataset_indices_by_size(src_sizes, tgt_sizes, indices, max_sizes):
+    """Filter a list of sample indices. Remove those that are longer
+        than specified in max_sizes.
+
+    Args:
+        indices (np.array): original array of sample indices
+        max_sizes (int or list[int] or tuple[int]): max sample size,
+            can be defined separately for src and tgt (then list or tuple)
+
+    Returns:
+        np.array: filtered sample array
+        list: list of removed indices
+    """
+    if max_sizes is None:
+        return indices, []
+    if type(max_sizes) in (int, float):
+        max_src_size, max_tgt_size = max_sizes, max_sizes
+    else:
+        max_src_size, max_tgt_size = max_sizes
+    if tgt_sizes is None:
+        ignored = indices[src_sizes[indices] > max_src_size]
+    else:
+        ignored = indices[
+            (src_sizes[indices] > max_src_size) | (tgt_sizes[indices] > max_tgt_size)
+        ]
+    if len(ignored) > 0:
+        if tgt_sizes is None:
+            indices = indices[src_sizes[indices] <= max_src_size]
+        else:
+            indices = indices[
+                (src_sizes[indices] <= max_src_size)
+                & (tgt_sizes[indices] <= max_tgt_size)
+            ]
+    return indices, ignored.tolist()
+
+
+def batch_by_size(
+    indices,
+    num_tokens_fn,
+    max_tokens=None,
+    max_sentences=None,
+    required_batch_size_multiple=1,
+    fixed_shapes=None,
+):
+    """
+    Yield mini-batches of indices bucketed by size. Batches may contain
+    sequences of different lengths.
+
+    Args:
+        indices (List[int]): ordered list of dataset indices
+        num_tokens_fn (callable): function that returns the number of tokens at
+            a given index
+        max_tokens (int, optional): max number of tokens in each batch
+            (default: None).
+        max_sentences (int, optional): max number of sentences in each
+            batch (default: None).
+        required_batch_size_multiple (int, optional): require batch size to
+            be less than N or a multiple of N (default: 1).
+        fixed_shapes (List[Tuple[int, int]], optional): if given, batches will
+            only be created with the given shapes. *max_sentences* and
+            *required_batch_size_multiple* will be ignored (default: None).
+    """
+    try:
+        from fairseq.data.data_utils_fast import (
+            batch_by_size_fast,
+            batch_fixed_shapes_fast,
+        )
+    except ImportError:
+        raise ImportError(
+            "Please build Cython components with: `pip install --editable .` "
+            "or `python setup.py build_ext --inplace`"
+        )
+
+    max_tokens = max_tokens if max_tokens is not None else -1
+    max_sentences = max_sentences if max_sentences is not None else -1
+    bsz_mult = required_batch_size_multiple
+
+    if not isinstance(indices, np.ndarray):
+        indices = np.fromiter(indices, dtype=np.int64, count=-1)
+
+    if fixed_shapes is None:
+        return batch_by_size_fast(
+            indices,
+            num_tokens_fn,
+            max_tokens,
+            max_sentences,
+            bsz_mult,
+        )
+    else:
+        fixed_shapes = np.array(fixed_shapes, dtype=np.int64)
+        sort_order = np.lexsort(
+            [
+                fixed_shapes[:, 1].argsort(),  # length
+                fixed_shapes[:, 0].argsort(),  # bsz
+            ]
+        )
+        fixed_shapes_sorted = fixed_shapes[sort_order]
+        return batch_fixed_shapes_fast(indices, num_tokens_fn, fixed_shapes_sorted)
+
+
+def post_process(sentence: str, symbol: str):
+    if symbol == "sentencepiece":
+        sentence = sentence.replace(" ", "").replace("\u2581", " ").strip()
+    elif symbol == "wordpiece":
+        sentence = sentence.replace(" ", "").replace("_", " ").strip()
+    elif symbol == "letter":
+        sentence = sentence.replace(" ", "").replace("|", " ").strip()
+    elif symbol == "_EOW":
+        sentence = sentence.replace(" ", "").replace("_EOW", " ").strip()
+    elif symbol is not None and symbol != "none":
+        sentence = (sentence + " ").replace(symbol, "").rstrip()
+    return sentence
+
+
+def compute_mask_indices(
+    shape: Tuple[int, int],
+    padding_mask: Optional[torch.Tensor],
+    mask_prob: float,
+    mask_length: int,
+    mask_type: str = "static",
+    mask_other: float = 0.0,
+    min_masks: int = 0,
+    no_overlap: bool = False,
+    min_space: int = 0,
+) -> np.ndarray:
+    """
+    Computes random mask spans for a given shape
+
+    Args:
+        shape: the the shape for which to compute masks.
+            should be of size 2 where first element is batch size and 2nd is timesteps
+        padding_mask: optional padding mask of the same size as shape, which will prevent masking padded elements
+        mask_prob: probability for each token to be chosen as start of the span to be masked. this will be multiplied by
+            number of timesteps divided by length of mask span to mask approximately this percentage of all elements.
+            however due to overlaps, the actual number will be smaller (unless no_overlap is True)
+        mask_type: how to compute mask lengths
+            static = fixed size
+            uniform = sample from uniform distribution [mask_other, mask_length*2]
+            normal = sample from normal distribution with mean mask_length and stdev mask_other. mask is min 1 element
+            poisson = sample from possion distribution with lambda = mask length
+        min_masks: minimum number of masked spans
+        no_overlap: if false, will switch to an alternative recursive algorithm that prevents spans from overlapping
+        min_space: only used if no_overlap is True, this is how many elements to keep unmasked between spans
+    """
+
+    bsz, all_sz = shape
+    mask = np.full((bsz, all_sz), False)
+
+    all_num_mask = int(
+        # add a random number for probabilistic rounding
+        mask_prob * all_sz / float(mask_length)
+        + np.random.rand()
+    )
+
+    all_num_mask = max(min_masks, all_num_mask)
+
+    mask_idcs = []
+    for i in range(bsz):
+        if padding_mask is not None:
+            sz = all_sz - padding_mask[i].long().sum().item()
+            num_mask = int(
+                # add a random number for probabilistic rounding
+                mask_prob * sz / float(mask_length)
+                + np.random.rand()
+            )
+            num_mask = max(min_masks, num_mask)
+        else:
+            sz = all_sz
+            num_mask = all_num_mask
+
+        if mask_type == "static":
+            lengths = np.full(num_mask, mask_length)
+        elif mask_type == "uniform":
+            lengths = np.random.randint(mask_other, mask_length * 2 + 1, size=num_mask)
+        elif mask_type == "normal":
+            lengths = np.random.normal(mask_length, mask_other, size=num_mask)
+            lengths = [max(1, int(round(x))) for x in lengths]
+        elif mask_type == "poisson":
+            lengths = np.random.poisson(mask_length, size=num_mask)
+            lengths = [int(round(x)) for x in lengths]
+        else:
+            raise Exception("unknown mask selection " + mask_type)
+
+        if sum(lengths) == 0:
+            lengths[0] = min(mask_length, sz - 1)
+
+        if no_overlap:
+            mask_idc = []
+
+            def arrange(s, e, length, keep_length):
+                span_start = np.random.randint(s, e - length)
+                mask_idc.extend(span_start + i for i in range(length))
+
+                new_parts = []
+                if span_start - s - min_space >= keep_length:
+                    new_parts.append((s, span_start - min_space + 1))
+                if e - span_start - keep_length - min_space > keep_length:
+                    new_parts.append((span_start + length + min_space, e))
+                return new_parts
+
+            parts = [(0, sz)]
+            min_length = min(lengths)
+            for length in sorted(lengths, reverse=True):
+                lens = np.fromiter(
+                    (e - s if e - s >= length + min_space else 0 for s, e in parts),
+                    np.int,
+                )
+                l_sum = np.sum(lens)
+                if l_sum == 0:
+                    break
+                probs = lens / np.sum(lens)
+                c = np.random.choice(len(parts), p=probs)
+                s, e = parts.pop(c)
+                parts.extend(arrange(s, e, length, min_length))
+            mask_idc = np.asarray(mask_idc)
+        else:
+            min_len = min(lengths)
+            if sz - min_len <= num_mask:
+                min_len = sz - num_mask - 1
+
+            mask_idc = np.random.choice(sz - min_len, num_mask, replace=False)
+
+            mask_idc = np.asarray(
+                [
+                    mask_idc[j] + offset
+                    for j in range(len(mask_idc))
+                    for offset in range(lengths[j])
+                ]
+            )
+
+        mask_idcs.append(np.unique(mask_idc[mask_idc < sz]))
+
+    min_len = min([len(m) for m in mask_idcs])
+    for i, mask_idc in enumerate(mask_idcs):
+        if len(mask_idc) > min_len:
+            mask_idc = np.random.choice(mask_idc, min_len, replace=False)
+        mask[i, mask_idc] = True
+
+    return mask
+
+
+def get_mem_usage():
+    try:
+        import psutil
+
+        mb = 1024 * 1024
+        return f"used={psutil.virtual_memory().used / mb}Mb; avail={psutil.virtual_memory().available / mb}Mb"
+    except ImportError:
+        return "N/A"
+
+
+def lengths_to_padding_mask(lens: torch.LongTensor) -> torch.BoolTensor:
+    bsz, max_lens = lens.size(0), torch.max(lens).item()
+    mask = torch.arange(max_lens).to(lens.device).view(1, max_lens)
+    mask = mask.expand(bsz, -1) >= lens.view(bsz, 1).expand(-1, max_lens)
+    return mask
+
+
+def lengths_to_mask(lens: torch.LongTensor) -> torch.BoolTensor:
+    return ~lengths_to_padding_mask(lens)

fairseq/data/data_utils_fast.pyx

@@ -0,0 +1,123 @@
+# cython: language_level=3
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import numpy as np
+
+cimport cython
+cimport numpy as np
+
+from libc.stdint cimport int32_t, int64_t
+
+ctypedef int64_t DTYPE_t
+
+
+cdef _is_batch_full(int64_t num_sentences, int64_t num_tokens, int64_t max_tokens, int64_t max_sentences):
+    if num_sentences == 0:
+        return 0
+    if max_sentences > 0 and num_sentences == max_sentences:
+        return 1
+    if max_tokens > 0 and num_tokens > max_tokens:
+        return 1
+    return 0
+
+
+@cython.cdivision(True)
+cpdef list batch_by_size_fast(
+    np.ndarray[DTYPE_t, ndim=1] indices,
+    num_tokens_fn,
+    int64_t max_tokens,
+    int64_t max_sentences,
+    int32_t bsz_mult,
+):
+    cdef int64_t sample_len = 0
+    cdef list sample_lens = []
+    cdef list batch = []
+    cdef list batches = []
+    cdef int64_t mod_len
+    cdef int64_t i
+    cdef int64_t idx
+    cdef int64_t num_tokens
+    cdef DTYPE_t[:] indices_view = indices
+
+    for i in range(len(indices_view)):
+        idx = indices_view[i]
+        num_tokens = num_tokens_fn(idx)
+        sample_lens.append(num_tokens)
+        sample_len = max(sample_len, num_tokens)
+
+        assert max_tokens <= 0 or sample_len <= max_tokens, (
+            "sentence at index {} of size {} exceeds max_tokens "
+            "limit of {}!".format(idx, sample_len, max_tokens)
+        )
+        num_tokens = (len(batch) + 1) * sample_len
+
+        if _is_batch_full(len(batch), num_tokens, max_tokens, max_sentences):
+            mod_len = max(
+                bsz_mult * (len(batch) // bsz_mult),
+                len(batch) % bsz_mult,
+            )
+            batches.append(batch[:mod_len])
+            batch = batch[mod_len:]
+            sample_lens = sample_lens[mod_len:]
+            sample_len = max(sample_lens) if len(sample_lens) > 0 else 0
+        batch.append(idx)
+    if len(batch) > 0:
+        batches.append(batch)
+    return batches
+
+
+cdef _find_valid_shape(
+    DTYPE_t[:, :] shapes_view,
+    int64_t num_sentences,
+    int64_t num_tokens,
+):
+    """Return index of first valid shape of -1 if none is found."""
+    for i in range(shapes_view.shape[0]):
+        if num_sentences <= shapes_view[i][0] and num_tokens <= shapes_view[i][1]:
+            return i
+    return -1
+
+
+@cython.cdivision(True)
+cpdef list batch_fixed_shapes_fast(
+    np.ndarray[DTYPE_t, ndim=1] indices,
+    num_tokens_fn,
+    np.ndarray[DTYPE_t, ndim=2] fixed_shapes_sorted,
+):
+    cdef int64_t sample_len = 0
+    cdef list sample_lens = []
+    cdef list batch = []
+    cdef list batches = []
+    cdef int64_t mod_len
+    cdef int64_t i
+    cdef int64_t idx
+    cdef int64_t num_tokens
+    cdef DTYPE_t[:] indices_view = indices
+    cdef DTYPE_t[:, :] shapes_view = fixed_shapes_sorted
+
+    for i in range(len(indices_view)):
+        idx = indices_view[i]
+        num_tokens = num_tokens_fn(idx)
+        sample_lens.append(num_tokens)
+        sample_len = max(sample_len, num_tokens)
+
+        shape_idx = _find_valid_shape(shapes_view, len(batch) + 1, sample_len)
+        if shape_idx == -1:
+            batches.append(batch)
+            batch = []
+            sample_lens = []
+            sample_len = 0
+            shapes_view = fixed_shapes_sorted
+        elif shape_idx > 0:
+            # small optimization for the next call to _find_valid_shape
+            shapes_view = shapes_view[shape_idx:]
+
+        batch.append(idx)
+
+    if len(batch) > 0:
+        batches.append(batch)
+
+    return batches

fairseq/data/dictionary.py

@@ -0,0 +1,418 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import os
+from collections import Counter
+from multiprocessing import Pool
+
+import torch
+from fairseq import utils
+from fairseq.binarizer import safe_readline
+from fairseq.data import data_utils
+from fairseq.file_io import PathManager
+from fairseq.tokenizer import tokenize_line
+
+
+class Dictionary(object):
+    """A mapping from symbols to consecutive integers"""
+
+    def __init__(
+        self,
+        input_file=None,  # begin keyword-only arguments
+        bos="<s>",
+        pad="<pad>",
+        eos="</s>",
+        unk="<unk>",
+        extra_special_symbols=None,
+    ):
+
+        self.symbols = []
+        self.count = []
+        self.indices = {}
+        if input_file is not None and 'json' in input_file:
+            self.add_from_json(input_file)
+        else:
+            self.add_from_file(input_file)            
+        self.bos_word, self.unk_word, self.pad_word, self.eos_word = bos, unk, pad, eos
+        self.bos_index = self.add_symbol(bos)
+        self.pad_index = self.add_symbol(pad)
+        self.eos_index = self.add_symbol(eos)
+        self.unk_index = self.add_symbol(unk)
+        if extra_special_symbols:
+            for s in extra_special_symbols:
+                self.add_symbol(s)
+        self.nspecial = len(self.symbols)
+
+    def __eq__(self, other):
+        return self.indices == other.indices
+
+    def __getitem__(self, idx):
+        if idx < len(self.symbols):
+            return self.symbols[idx]
+        return self.unk_word
+
+    def __len__(self):
+        """Returns the number of symbols in the dictionary"""
+        return len(self.symbols)
+
+    def __contains__(self, sym):
+        return sym in self.indices
+
+    def index(self, sym):
+        """Returns the index of the specified symbol"""
+        assert isinstance(sym, str)
+        if sym in self.indices:
+            return self.indices[sym]
+        return self.unk_index
+
+    def string(
+        self,
+        tensor,
+        bpe_symbol=None,
+        escape_unk=False,
+        extra_symbols_to_ignore=None,
+        unk_string=None,
+    ):
+        """Helper for converting a tensor of token indices to a string.
+
+        Can optionally remove BPE symbols or escape <unk> words.
+        """
+        if torch.is_tensor(tensor) and tensor.dim() == 2:
+            return "\n".join(
+                self.string(t, bpe_symbol, escape_unk, extra_symbols_to_ignore)
+                for t in tensor
+            )
+
+        extra_symbols_to_ignore = set(extra_symbols_to_ignore or [])
+        extra_symbols_to_ignore.add(self.eos())
+
+        def token_string(i):
+            if i == self.unk():
+                if unk_string is not None:
+                    return unk_string
+                else:
+                    return self.unk_string(escape_unk)
+            else:
+                return self[i]
+
+        if hasattr(self, "bos_index"):
+            extra_symbols_to_ignore.add(self.bos())
+
+        sent = " ".join(
+            token_string(i)
+            for i in tensor
+            if utils.item(i) not in extra_symbols_to_ignore
+        )
+
+        return data_utils.post_process(sent, bpe_symbol)
+
+    def unk_string(self, escape=False):
+        """Return unknown string, optionally escaped as: <<unk>>"""
+        if escape:
+            return "<{}>".format(self.unk_word)
+        else:
+            return self.unk_word
+
+    def add_symbol(self, word, n=1, overwrite=False):
+        """Adds a word to the dictionary"""
+        if word in self.indices and not overwrite:
+            idx = self.indices[word]
+            self.count[idx] = self.count[idx] + n
+            return idx
+        else:
+            idx = len(self.symbols)
+            self.indices[word] = idx
+            self.symbols.append(word)
+            self.count.append(n)
+            return idx
+
+    def update(self, new_dict):
+        """Updates counts from new dictionary."""
+        for word in new_dict.symbols:
+            idx2 = new_dict.indices[word]
+            if word in self.indices:
+                idx = self.indices[word]
+                self.count[idx] = self.count[idx] + new_dict.count[idx2]
+            else:
+                idx = len(self.symbols)
+                self.indices[word] = idx
+                self.symbols.append(word)
+                self.count.append(new_dict.count[idx2])
+
+    def finalize(self, threshold=-1, nwords=-1, padding_factor=8):
+        """Sort symbols by frequency in descending order, ignoring special ones.
+
+        Args:
+            - threshold defines the minimum word count
+            - nwords defines the total number of words in the final dictionary,
+                including special symbols
+            - padding_factor can be used to pad the dictionary size to be a
+                multiple of 8, which is important on some hardware (e.g., Nvidia
+                Tensor Cores).
+        """
+        if nwords <= 0:
+            nwords = len(self)
+
+        new_indices = dict(zip(self.symbols[: self.nspecial], range(self.nspecial)))
+        new_symbols = self.symbols[: self.nspecial]
+        new_count = self.count[: self.nspecial]
+
+        c = Counter(
+            dict(
+                sorted(zip(self.symbols[self.nspecial :], self.count[self.nspecial :]))
+            )
+        )
+        for symbol, count in c.most_common(nwords - self.nspecial):
+            if count >= threshold:
+                new_indices[symbol] = len(new_symbols)
+                new_symbols.append(symbol)
+                new_count.append(count)
+            else:
+                break
+
+        assert len(new_symbols) == len(new_indices)
+
+        self.count = list(new_count)
+        self.symbols = list(new_symbols)
+        self.indices = new_indices
+
+        self.pad_to_multiple_(padding_factor)
+
+    def pad_to_multiple_(self, padding_factor):
+        """Pad Dictionary size to be a multiple of *padding_factor*."""
+        if padding_factor > 1:
+            i = 0
+            while len(self) % padding_factor != 0:
+                symbol = "madeupword{:04d}".format(i)
+                self.add_symbol(symbol, n=0)
+                i += 1
+
+    def bos(self):
+        """Helper to get index of beginning-of-sentence symbol"""
+        return self.bos_index
+
+    def pad(self):
+        """Helper to get index of pad symbol"""
+        return self.pad_index
+
+    def eos(self):
+        """Helper to get index of end-of-sentence symbol"""
+        return self.eos_index
+
+    def unk(self):
+        """Helper to get index of unk symbol"""
+        return self.unk_index
+
+    @classmethod
+    def load(cls, f):
+        """Loads the dictionary from a text file with the format:
+
+        ```
+        <symbol0> <count0>
+        <symbol1> <count1>
+        ...
+        ```
+        """
+        d = cls()
+        d.add_from_file(f)
+        return d
+
+    @classmethod
+    def load_from_json(cls, f):
+        d = cls()
+        d.add_from_json(f)
+        return d
+
+    def add_from_json(self, f):
+        import json
+        if isinstance(f, str):
+            try:
+                with open(PathManager.get_local_path(f), "r", encoding="utf-8") as fd:
+                    self.add_from_json(fd)
+            except FileNotFoundError as fnfe:
+                raise fnfe
+            except UnicodeError:
+                raise Exception(
+                    "Incorrect encoding detected in {}, please "
+                    "rebuild the dataset".format(f)
+                )
+            return
+
+        vocab = json.load(f)
+        for k, v in vocab.items():
+            self.add_symbol(k)
+        
+
+    def add_from_file(self, f):
+        """
+        Loads a pre-existing dictionary from a text file and adds its symbols
+        to this instance.
+        """
+        if isinstance(f, str):
+            try:
+                with open(PathManager.get_local_path(f), "r", encoding="utf-8") as fd:
+                    self.add_from_file(fd)
+            except FileNotFoundError as fnfe:
+                raise fnfe
+            except UnicodeError:
+                raise Exception(
+                    "Incorrect encoding detected in {}, please "
+                    "rebuild the dataset".format(f)
+                )
+            return
+
+        lines = f.readlines()
+        indices_start_line = self._load_meta(lines)
+
+        for line in lines[indices_start_line:]:
+            try:
+                line, field = line.rstrip().rsplit(" ", 1)
+                if field == "#fairseq:overwrite":
+                    overwrite = True
+                    line, field = line.rsplit(" ", 1)
+                else:
+                    overwrite = False
+                count = int(field)
+                word = line
+                if word in self and not overwrite:
+                    raise RuntimeError(
+                        "Duplicate word found when loading Dictionary: '{}'. "
+                        "Duplicate words can overwrite earlier ones by adding the "
+                        "#fairseq:overwrite flag at the end of the corresponding row "
+                        "in the dictionary file. If using the Camembert model, please "
+                        "download an updated copy of the model file.".format(word)
+                    )
+                self.add_symbol(word, n=count, overwrite=overwrite)
+            except ValueError:
+                raise ValueError(
+                    "Incorrect dictionary format, expected '<token> <cnt> [flags]'"
+                )
+
+    def _save(self, f, kv_iterator):
+        if isinstance(f, str):
+            PathManager.mkdirs(os.path.dirname(f))
+            with PathManager.open(f, "w", encoding="utf-8") as fd:
+                return self.save(fd)
+        for k, v in kv_iterator:
+            print("{} {}".format(k, v), file=f)
+
+    def _get_meta(self):
+        return [], []
+
+    def _load_meta(self, lines):
+        return 0
+
+    def save(self, f):
+        """Stores dictionary into a text file"""
+        ex_keys, ex_vals = self._get_meta()
+        self._save(
+            f,
+            zip(
+                ex_keys + self.symbols[self.nspecial :],
+                ex_vals + self.count[self.nspecial :],
+            ),
+        )
+
+    def dummy_sentence(self, length):
+        t = torch.Tensor(length).uniform_(self.nspecial + 1, len(self)).long()
+        t[-1] = self.eos()
+        return t
+
+    def encode_line(
+        self,
+        line,
+        line_tokenizer=tokenize_line,
+        add_if_not_exist=True,
+        consumer=None,
+        append_eos=True,
+        reverse_order=False,
+    ):
+        words = line_tokenizer(line)
+        if reverse_order:
+            words = list(reversed(words))
+        nwords = len(words)
+        ids = torch.IntTensor(nwords + 1 if append_eos else nwords)
+
+        for i, word in enumerate(words):
+            if add_if_not_exist:
+                idx = self.add_symbol(word)
+            else:
+                idx = self.index(word)
+            if consumer is not None:
+                consumer(word, idx)
+            ids[i] = idx
+        if append_eos:
+            ids[nwords] = self.eos_index
+        return ids
+
+    @staticmethod
+    def _add_file_to_dictionary_single_worker(
+        filename, tokenize, eos_word, worker_id=0, num_workers=1
+    ):
+        counter = Counter()
+        with open(PathManager.get_local_path(filename), "r", encoding="utf-8") as f:
+            size = os.fstat(f.fileno()).st_size
+            chunk_size = size // num_workers
+            offset = worker_id * chunk_size
+            end = offset + chunk_size
+            f.seek(offset)
+            if offset > 0:
+                safe_readline(f)  # drop first incomplete line
+            line = f.readline()
+            while line:
+                for word in tokenize(line):
+                    counter.update([word])
+                counter.update([eos_word])
+                if f.tell() > end:
+                    break
+                line = f.readline()
+        return counter
+
+    @staticmethod
+    def add_file_to_dictionary(filename, dict, tokenize, num_workers):
+        def merge_result(counter):
+            for w, c in sorted(counter.items()):
+                dict.add_symbol(w, c)
+
+        if num_workers > 1:
+            pool = Pool(processes=num_workers)
+            results = []
+            for worker_id in range(num_workers):
+                results.append(
+                    pool.apply_async(
+                        Dictionary._add_file_to_dictionary_single_worker,
+                        (filename, tokenize, dict.eos_word, worker_id, num_workers),
+                    )
+                )
+            pool.close()
+            pool.join()
+            for r in results:
+                merge_result(r.get())
+        else:
+            merge_result(
+                Dictionary._add_file_to_dictionary_single_worker(
+                    filename, tokenize, dict.eos_word
+                )
+            )
+
+
+class TruncatedDictionary(object):
+    def __init__(self, wrapped_dict, length):
+        self.__class__ = type(
+            wrapped_dict.__class__.__name__,
+            (self.__class__, wrapped_dict.__class__),
+            {},
+        )
+        self.__dict__ = wrapped_dict.__dict__
+        self.wrapped_dict = wrapped_dict
+        self.length = min(len(self.wrapped_dict), length)
+
+    def __len__(self):
+        return self.length
+
+    def __getitem__(self, i):
+        if i < self.length:
+            return self.wrapped_dict[i]
+        return self.wrapped_dict.unk()

fairseq/data/encoders/__init__.py

@@ -0,0 +1,29 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+
+import importlib
+import os
+
+from fairseq import registry
+
+
+build_tokenizer, register_tokenizer, TOKENIZER_REGISTRY, _ = registry.setup_registry(
+    "--tokenizer",
+    default=None,
+)
+
+
+build_bpe, register_bpe, BPE_REGISTRY, _ = registry.setup_registry(
+    "--bpe",
+    default=None,
+)
+
+
+# automatically import any Python files in the encoders/ directory
+for file in os.listdir(os.path.dirname(__file__)):
+    if file.endswith(".py") and not file.startswith("_"):
+        module = file[: file.find(".py")]
+        importlib.import_module("fairseq.data.encoders." + module)

fairseq/data/encoders/byte_bpe.py

@@ -0,0 +1,48 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+
+from dataclasses import dataclass, field
+
+from fairseq import file_utils
+from fairseq.data.encoders import register_bpe
+from fairseq.data.encoders.byte_utils import (
+    SPACE,
+    SPACE_ESCAPE,
+    byte_encode,
+    smart_byte_decode,
+)
+from fairseq.dataclass import FairseqDataclass
+
+
+@dataclass
+class ByteBpeConfig(FairseqDataclass):
+    sentencepiece_model_path: str = field(
+        default="???", metadata={"help": "path to sentencepiece model"}
+    )
+
+
+@register_bpe("byte_bpe", dataclass=ByteBpeConfig)
+class ByteBPE(object):
+    def __init__(self, cfg):
+        vocab = file_utils.cached_path(cfg.sentencepiece_model_path)
+        try:
+            import sentencepiece as spm
+
+            self.sp = spm.SentencePieceProcessor()
+            self.sp.Load(vocab)
+        except ImportError:
+            raise ImportError(
+                "Please install sentencepiece with: pip install sentencepiece"
+            )
+
+    def encode(self, x: str) -> str:
+        byte_encoded = byte_encode(x)
+        return SPACE.join(self.sp.EncodeAsPieces(byte_encoded))
+
+    @staticmethod
+    def decode(x: str) -> str:
+        unescaped = x.replace(SPACE, "").replace(SPACE_ESCAPE, SPACE)
+        return smart_byte_decode(unescaped)

fairseq/data/encoders/byte_utils.py

@@ -0,0 +1,51 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import re
+
+
+WHITESPACE_NORMALIZER = re.compile(r"\s+")
+SPACE = chr(32)
+SPACE_ESCAPE = chr(9601)
+# excluding non-breaking space (160) here
+PRINTABLE_LATIN = set(
+    list(range(32, 126 + 1)) + list(range(161, 172 + 1)) + list(range(174, 255 + 1))
+)
+BYTE_TO_BCHAR = {
+    b: chr(b) if b in PRINTABLE_LATIN else chr(256 + b) for b in range(256)
+}
+BCHAR_TO_BYTE = {bc: b for b, bc in BYTE_TO_BCHAR.items()}
+
+
+def byte_encode(x: str) -> str:
+    normalized = WHITESPACE_NORMALIZER.sub(SPACE, x)
+    return "".join([BYTE_TO_BCHAR[b] for b in normalized.encode("utf-8")])
+
+
+def byte_decode(x: str) -> str:
+    try:
+        return bytes([BCHAR_TO_BYTE[bc] for bc in x]).decode("utf-8")
+    except ValueError:
+        return ""
+
+
+def smart_byte_decode(x: str) -> str:
+    output = byte_decode(x)
+    if output == "":
+        # DP the best recovery (max valid chars) if it's broken
+        n_bytes = len(x)
+        f = [0 for _ in range(n_bytes + 1)]
+        pt = [0 for _ in range(n_bytes + 1)]
+        for i in range(1, n_bytes + 1):
+            f[i], pt[i] = f[i - 1], i - 1
+            for j in range(1, min(4, i) + 1):
+                if f[i - j] + 1 > f[i] and len(byte_decode(x[i - j : i])) > 0:
+                    f[i], pt[i] = f[i - j] + 1, i - j
+        cur_pt = n_bytes
+        while cur_pt > 0:
+            if f[cur_pt] == f[pt[cur_pt]] + 1:
+                output = byte_decode(x[pt[cur_pt] : cur_pt]) + output
+            cur_pt = pt[cur_pt]
+    return output

fairseq/data/encoders/bytes.py

@@ -0,0 +1,34 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+
+from fairseq.data.encoders import register_bpe
+from fairseq.data.encoders.byte_utils import (
+    SPACE,
+    SPACE_ESCAPE,
+    byte_encode,
+    smart_byte_decode,
+)
+
+
+@register_bpe("bytes")
+class Bytes(object):
+    def __init__(self, *unused):
+        pass
+
+    @staticmethod
+    def add_args(parser):
+        pass
+
+    @staticmethod
+    def encode(x: str) -> str:
+        encoded = byte_encode(x)
+        escaped = encoded.replace(SPACE, SPACE_ESCAPE)
+        return SPACE.join(list(escaped))
+
+    @staticmethod
+    def decode(x: str) -> str:
+        unescaped = x.replace(SPACE, "").replace(SPACE_ESCAPE, SPACE)
+        return smart_byte_decode(unescaped)

fairseq/data/encoders/characters.py

@@ -0,0 +1,30 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+
+from fairseq.data.encoders import register_bpe
+
+
+SPACE = chr(32)
+SPACE_ESCAPE = chr(9601)
+
+
+@register_bpe("characters")
+class Characters(object):
+    def __init__(self, *unused):
+        pass
+
+    @staticmethod
+    def add_args(parser):
+        pass
+
+    @staticmethod
+    def encode(x: str) -> str:
+        escaped = x.replace(SPACE, SPACE_ESCAPE)
+        return SPACE.join(list(escaped))
+
+    @staticmethod
+    def decode(x: str) -> str:
+        return x.replace(SPACE, "").replace(SPACE_ESCAPE, SPACE)

fairseq/data/encoders/fastbpe.py

@@ -0,0 +1,36 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from dataclasses import dataclass, field
+
+from fairseq import file_utils
+from fairseq.data.encoders import register_bpe
+from fairseq.dataclass import FairseqDataclass
+
+
+@dataclass
+class fastBPEConfig(FairseqDataclass):
+    bpe_codes: str = field(default="???", metadata={"help": "path to fastBPE BPE"})
+
+
+@register_bpe("fastbpe", dataclass=fastBPEConfig)
+class fastBPE(object):
+    def __init__(self, cfg):
+        if cfg.bpe_codes is None:
+            raise ValueError("--bpe-codes is required for --bpe=fastbpe")
+        codes = file_utils.cached_path(cfg.bpe_codes)
+        try:
+            import fastBPE
+
+            self.bpe = fastBPE.fastBPE(codes)
+            self.bpe_symbol = "@@ "
+        except ImportError:
+            raise ImportError("Please install fastBPE with: pip install fastBPE")
+
+    def encode(self, x: str) -> str:
+        return self.bpe.apply([x])[0]
+
+    def decode(self, x: str) -> str:
+        return (x + " ").replace(self.bpe_symbol, "").rstrip()

fairseq/data/encoders/gpt2_bpe.py

@@ -0,0 +1,45 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from dataclasses import dataclass, field
+
+from fairseq import file_utils
+from fairseq.data.encoders import register_bpe
+from fairseq.dataclass import FairseqDataclass
+
+from .gpt2_bpe_utils import get_encoder
+
+
+DEFAULT_ENCODER_JSON = "https://dl.fbaipublicfiles.com/fairseq/gpt2_bpe/encoder.json"
+DEFAULT_VOCAB_BPE = "https://dl.fbaipublicfiles.com/fairseq/gpt2_bpe/vocab.bpe"
+
+
+@dataclass
+class GPT2BPEConfig(FairseqDataclass):
+    gpt2_encoder_json: str = field(
+        default=DEFAULT_ENCODER_JSON, metadata={"help": "path to encoder.json"}
+    )
+    gpt2_vocab_bpe: str = field(
+        default=DEFAULT_VOCAB_BPE, metadata={"help": "path to vocab.bpe"}
+    )
+
+
+@register_bpe("gpt2", dataclass=GPT2BPEConfig)
+class GPT2BPE(object):
+    def __init__(self, cfg):
+        encoder_json = file_utils.cached_path(cfg.gpt2_encoder_json)
+        vocab_bpe = file_utils.cached_path(cfg.gpt2_vocab_bpe)
+        self.bpe = get_encoder(encoder_json, vocab_bpe)
+
+    def encode(self, x: str) -> str:
+        return " ".join(map(str, self.bpe.encode(x)))
+
+    def decode(self, x: str) -> str:
+        return self.bpe.decode(
+            [int(tok) if tok not in {"<unk>", "<mask>"} else tok for tok in x.split()]
+        )
+
+    def is_beginning_of_word(self, x: str) -> bool:
+        return self.decode(x).startswith(" ")

fairseq/data/encoders/gpt2_bpe_utils.py

@@ -0,0 +1,140 @@
+"""
+Byte pair encoding utilities from GPT-2.
+
+Original source: https://github.com/openai/gpt-2/blob/master/src/encoder.py
+Original license: MIT
+"""
+
+import json
+from functools import lru_cache
+
+
+@lru_cache()
+def bytes_to_unicode():
+    """
+    Returns list of utf-8 byte and a corresponding list of unicode strings.
+    The reversible bpe codes work on unicode strings.
+    This means you need a large # of unicode characters in your vocab if you want to avoid UNKs.
+    When you're at something like a 10B token dataset you end up needing around 5K for decent coverage.
+    This is a signficant percentage of your normal, say, 32K bpe vocab.
+    To avoid that, we want lookup tables between utf-8 bytes and unicode strings.
+    And avoids mapping to whitespace/control characters the bpe code barfs on.
+    """
+    bs = (
+        list(range(ord("!"), ord("~") + 1))
+        + list(range(ord("¡"), ord("¬") + 1))
+        + list(range(ord("®"), ord("ÿ") + 1))
+    )
+    cs = bs[:]
+    n = 0
+    for b in range(2 ** 8):
+        if b not in bs:
+            bs.append(b)
+            cs.append(2 ** 8 + n)
+            n += 1
+    cs = [chr(n) for n in cs]
+    return dict(zip(bs, cs))
+
+
+def get_pairs(word):
+    """Return set of symbol pairs in a word.
+    Word is represented as tuple of symbols (symbols being variable-length strings).
+    """
+    pairs = set()
+    prev_char = word[0]
+    for char in word[1:]:
+        pairs.add((prev_char, char))
+        prev_char = char
+    return pairs
+
+
+class Encoder:
+    def __init__(self, encoder, bpe_merges, errors="replace"):
+        self.encoder = encoder
+        self.decoder = {v: k for k, v in self.encoder.items()}
+        self.errors = errors  # how to handle errors in decoding
+        self.byte_encoder = bytes_to_unicode()
+        self.byte_decoder = {v: k for k, v in self.byte_encoder.items()}
+        self.bpe_ranks = dict(zip(bpe_merges, range(len(bpe_merges))))
+        self.cache = {}
+
+        try:
+            import regex as re
+
+            self.re = re
+        except ImportError:
+            raise ImportError("Please install regex with: pip install regex")
+
+        # Should haved added re.IGNORECASE so BPE merges can happen for capitalized versions of contractions
+        self.pat = self.re.compile(
+            r"""'s|'t|'re|'ve|'m|'ll|'d| ?\p{L}+| ?\p{N}+| ?[^\s\p{L}\p{N}]+|\s+(?!\S)|\s+"""
+        )
+
+    def bpe(self, token):
+        if token in self.cache:
+            return self.cache[token]
+        word = tuple(token)
+        pairs = get_pairs(word)
+
+        if not pairs:
+            return token
+
+        while True:
+            bigram = min(pairs, key=lambda pair: self.bpe_ranks.get(pair, float("inf")))
+            if bigram not in self.bpe_ranks:
+                break
+            first, second = bigram
+            new_word = []
+            i = 0
+            while i < len(word):
+                try:
+                    j = word.index(first, i)
+                    new_word.extend(word[i:j])
+                    i = j
+                except:
+                    new_word.extend(word[i:])
+                    break
+
+                if word[i] == first and i < len(word) - 1 and word[i + 1] == second:
+                    new_word.append(first + second)
+                    i += 2
+                else:
+                    new_word.append(word[i])
+                    i += 1
+            new_word = tuple(new_word)
+            word = new_word
+            if len(word) == 1:
+                break
+            else:
+                pairs = get_pairs(word)
+        word = " ".join(word)
+        self.cache[token] = word
+        return word
+
+    def encode(self, text):
+        bpe_tokens = []
+        for token in self.re.findall(self.pat, text):
+            token = "".join(self.byte_encoder[b] for b in token.encode("utf-8"))
+            bpe_tokens.extend(
+                self.encoder[bpe_token] for bpe_token in self.bpe(token).split(" ")
+            )
+        return bpe_tokens
+
+    def decode(self, tokens):
+        text = "".join([self.decoder.get(token, token) for token in tokens])
+        text = bytearray([self.byte_decoder[c] for c in text]).decode(
+            "utf-8", errors=self.errors
+        )
+        return text
+
+
+def get_encoder(encoder_json_path, vocab_bpe_path):
+    with open(encoder_json_path, "r") as f:
+        encoder = json.load(f)
+    with open(vocab_bpe_path, "r", encoding="utf-8") as f:
+        bpe_data = f.read()
+    bpe_merges = [tuple(merge_str.split()) for merge_str in bpe_data.split("\n")[1:-1]]
+    return Encoder(
+        encoder=encoder,
+        bpe_merges=bpe_merges,
+    )

fairseq/data/encoders/hf_bert_bpe.py

@@ -0,0 +1,50 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from dataclasses import dataclass, field
+from typing import Optional
+
+from fairseq.data.encoders import register_bpe
+from fairseq.dataclass import FairseqDataclass
+
+
+@dataclass
+class BertBPEConfig(FairseqDataclass):
+    bpe_cased: bool = field(default=False, metadata={"help": "set for cased BPE"})
+    bpe_vocab_file: Optional[str] = field(
+        default=None, metadata={"help": "bpe vocab file"}
+    )
+
+
+@register_bpe("bert", dataclass=BertBPEConfig)
+class BertBPE(object):
+    def __init__(self, cfg):
+        try:
+            from transformers import BertTokenizer
+        except ImportError:
+            raise ImportError(
+                "Please install transformers with: pip install transformers"
+            )
+
+        if cfg.bpe_vocab_file:
+            self.bert_tokenizer = BertTokenizer(
+                cfg.bpe_vocab_file, do_lower_case=not cfg.bpe_cased
+            )
+        else:
+            vocab_file_name = (
+                "bert-base-cased" if cfg.bpe_cased else "bert-base-uncased"
+            )
+            self.bert_tokenizer = BertTokenizer.from_pretrained(vocab_file_name)
+
+    def encode(self, x: str) -> str:
+        return " ".join(self.bert_tokenizer.tokenize(x))
+
+    def decode(self, x: str) -> str:
+        return self.bert_tokenizer.clean_up_tokenization(
+            self.bert_tokenizer.convert_tokens_to_string(x.split(" "))
+        )
+
+    def is_beginning_of_word(self, x: str) -> bool:
+        return not x.startswith("##")

fairseq/data/encoders/hf_byte_bpe.py

@@ -0,0 +1,46 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from dataclasses import dataclass, field
+
+from fairseq.data.encoders import register_bpe
+from fairseq.dataclass import FairseqDataclass
+
+
+@dataclass
+class HuggingFaceByteLevelBPEConfig(FairseqDataclass):
+    bpe_merges: str = field(default="???", metadata={"help": "path to merges.txt"})
+    bpe_vocab: str = field(default="???", metadata={"help": "path to vocab.json"})
+    bpe_add_prefix_space: bool = field(
+        default=False, metadata={"help": "add prefix space before encoding"}
+    )
+
+
+@register_bpe("hf_byte_bpe", dataclass=HuggingFaceByteLevelBPEConfig)
+class HuggingFaceByteLevelBPE(object):
+    def __init__(self, cfg):
+        try:
+            from tokenizers import ByteLevelBPETokenizer
+        except ImportError:
+            raise ImportError(
+                "Please install huggingface/tokenizers with: " "pip install tokenizers"
+            )
+
+        self.bpe = ByteLevelBPETokenizer(
+            cfg.bpe_vocab,
+            cfg.bpe_merges,
+            add_prefix_space=cfg.bpe_add_prefix_space,
+        )
+
+    def encode(self, x: str) -> str:
+        return " ".join(map(str, self.bpe.encode(x).ids))
+
+    def decode(self, x: str) -> str:
+        return self.bpe.decode(
+            [int(tok) if tok not in {"<unk>", "<mask>"} else tok for tok in x.split()]
+        )
+
+    def is_beginning_of_word(self, x: str) -> bool:
+        return self.decode(x).startswith(" ")

fairseq/data/encoders/moses_tokenizer.py

@@ -0,0 +1,49 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from dataclasses import dataclass, field
+
+from fairseq.data.encoders import register_tokenizer
+from fairseq.dataclass import FairseqDataclass
+
+
+@dataclass
+class MosesTokenizerConfig(FairseqDataclass):
+    source_lang: str = field(default="en", metadata={"help": "source language"})
+    target_lang: str = field(default="en", metadata={"help": "target language"})
+    moses_no_dash_splits: bool = field(
+        default=False, metadata={"help": "don't apply dash split rules"}
+    )
+    moses_no_escape: bool = field(
+        default=False,
+        metadata={"help": "don't perform HTML escaping on apostrophe, quotes, etc."},
+    )
+
+
+@register_tokenizer("moses", dataclass=MosesTokenizerConfig)
+class MosesTokenizer(object):
+    def __init__(self, cfg):
+        self.cfg = cfg
+
+        try:
+            from sacremoses import MosesTokenizer, MosesDetokenizer
+
+            self.tok = MosesTokenizer(cfg.source_lang)
+            self.detok = MosesDetokenizer(cfg.target_lang)
+        except ImportError:
+            raise ImportError(
+                "Please install Moses tokenizer with: pip install sacremoses"
+            )
+
+    def encode(self, x: str) -> str:
+        return self.tok.tokenize(
+            x,
+            aggressive_dash_splits=(not self.cfg.moses_no_dash_splits),
+            return_str=True,
+            escape=(not self.cfg.moses_no_escape),
+        )
+
+    def decode(self, x: str) -> str:
+        return self.detok.detokenize(x.split())

fairseq/data/encoders/nltk_tokenizer.py

@@ -0,0 +1,23 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from fairseq.data.encoders import register_tokenizer
+
+
+@register_tokenizer("nltk")
+class NLTKTokenizer(object):
+    def __init__(self, *unused):
+        try:
+            from nltk.tokenize import word_tokenize
+
+            self.word_tokenize = word_tokenize
+        except ImportError:
+            raise ImportError("Please install nltk with: pip install nltk")
+
+    def encode(self, x: str) -> str:
+        return " ".join(self.word_tokenize(x))
+
+    def decode(self, x: str) -> str:
+        return x

fairseq/data/encoders/sentencepiece_bpe.py

@@ -0,0 +1,48 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from dataclasses import dataclass, field
+
+from fairseq import file_utils
+from fairseq.data.encoders import register_bpe
+from fairseq.dataclass import FairseqDataclass
+
+
+@dataclass
+class SentencepieceConfig(FairseqDataclass):
+    sentencepiece_model: str = field(
+        default="???", metadata={"help": "path to sentencepiece model"}
+    )
+
+
+@register_bpe("sentencepiece", dataclass=SentencepieceConfig)
+class SentencepieceBPE(object):
+    def __init__(self, cfg):
+        sentencepiece_model = file_utils.cached_path(cfg.sentencepiece_model)
+        try:
+            import sentencepiece as spm
+
+            self.sp = spm.SentencePieceProcessor()
+            self.sp.Load(sentencepiece_model)
+        except ImportError:
+            raise ImportError(
+                "Please install sentencepiece with: pip install sentencepiece"
+            )
+
+    def encode(self, x: str) -> str:
+        return " ".join(self.sp.EncodeAsPieces(x))
+
+    def decode(self, x: str) -> str:
+        return x.replace(" ", "").replace("\u2581", " ").strip()
+
+    def is_beginning_of_word(self, x: str) -> bool:
+        if x in ["<unk>", "<s>", "</s>", "<pad>"]:
+            # special elements are always considered beginnings
+            # HACK: this logic is already present in fairseq/tasks/masked_lm.py
+            # but these special tokens are also contained in the sentencepiece
+            # vocabulary which causes duplicate special tokens. This hack makes
+            # sure that they are all taken into account.
+            return True
+        return x.startswith("\u2581")