[FRONTEND][ONNX]LRN support for ONNX (#1518)

* LRN support for ONNX

* [ONNX] Updated lrn testcases

nnvm/python/nnvm/frontend/onnx.py

@@ -499,6 +499,23 @@ class Gather(OnnxOpConverter):
         params[name] = indices
         return _sym.take(inputs[0], gather_indices, axis=axis)
 
+class LRN(OnnxOpConverter):
+    """ Operator converter for Local Response Normalization.
+    """
+    @classmethod
+    def _impl_v1(cls, inputs, attr, params):
+        """LRN support only NCHW format
+        https://github.com/onnx/onnx/blob/master/docs/Operators.md#LRN
+        """
+        axis = 1
+        alpha = attr.get('alpha', 0.0001)
+        beta = attr.get('beta', 0.75)
+        bias = attr.get('bias', 1.0)
+        nsize = attr.get('size')
+        return _sym.lrn(inputs[0], size=nsize, axis=axis,
+                        alpha=alpha, beta=beta, bias=bias)
+
+
 # compatible operators that do NOT require any conversion.
 _identity_list = []
 
@@ -586,7 +603,7 @@ def _get_convert_map(opset):
         # 'LpNormalization'
         'Dropout': AttrCvt('dropout', {'ratio': 'rate'}, ignores=['is_test']),
         'Flatten': Renamer('flatten'),
-        # 'LRN'
+        'LRN': LRN.get_converter(opset),
 
         # defs/reduction
         'ReduceMax': AttrCvt('max', {'axes', 'axis'}),

nnvm/tests/python/frontend/onnx/test_forward.py

@@ -1,4 +1,5 @@
 import numpy as np
+import math
 import nnvm
 import tvm
 from tvm.contrib import graph_runtime
@@ -312,6 +313,58 @@ def test_matmul():
 
         np.testing.assert_allclose(np.matmul(a_array, b_array), tvm_out.asnumpy(), rtol=1e-5, atol=1e-5)
 
+def verify_lrn(shape, nsize, dtype, alpha=None, beta=None, bias=None):
+    in_array = np.random.uniform(size=shape).astype(dtype)
+
+    if alpha == None and beta == None and bias==None:
+        alpha = 0.0001
+        beta = 0.75
+        bias = 1.0
+        node = onnx.helper.make_node('LRN', inputs=['in'], outputs=['out'], size=nsize)
+    else:
+        node = onnx.helper.make_node('LRN', inputs=['in'], outputs=['out'], alpha=alpha,
+                                     beta=beta, bias=bias, size=nsize)
+
+    graph = helper.make_graph([node],
+                              "lrn_test",
+                              inputs = [helper.make_tensor_value_info("in", TensorProto.FLOAT, list(shape))],
+                              outputs = [helper.make_tensor_value_info("out", TensorProto.FLOAT, list(shape))])
+    model = helper.make_model(graph, producer_name='lrn_test')
+
+    def _get_python_lrn():
+        square_sum = np.zeros(shape).astype(dtype)
+        for n, c, h, w in np.ndindex(in_array.shape):
+            square_sum[n, c, h, w] = sum(in_array[n,
+                                         max(0, c - int(math.floor((nsize - 1) / 2))): \
+                                             min(5, c + int(math.ceil((nsize - 1) / 2)) + 1),
+                                         h,
+                                         w] ** 2)
+        py_out = in_array / ((bias + (alpha / nsize) * square_sum) ** beta)
+        return py_out
+
+    for target, ctx in ctx_list():
+        new_sym, params = nnvm.frontend.from_onnx(model)
+
+        input_name = model.graph.input[0].name
+        shape_dict = {input_name: in_array.shape}
+        dtype_dict = {input_name: dtype}
+        graph, lib, params = nnvm.compiler.build(new_sym, target,
+                                                 shape_dict, dtype_dict, params=params)
+        m = graph_runtime.create(graph, lib, ctx)
+        # set inputs
+        m.set_input(input_name, tvm.nd.array(in_array.astype(dtype)))
+        m.set_input(**params)
+        m.run()
+        # get outputs
+        tvm_out = m.get_output(0, tvm.nd.empty(shape, dtype))
+        py_out = _get_python_lrn()
+        np.testing.assert_allclose(py_out, tvm_out.asnumpy(), rtol=1e-5, atol=1e-5)
+
+def test_lrn():
+    verify_lrn((5, 5, 5, 5), 3, 'float32')
+    verify_lrn((5, 5, 5, 5), 3, 'float32', alpha=0.0002, beta=0.5, bias=2.0)
+
+
 if __name__ == '__main__':
     # verify_super_resolution_example()
     # verify_squeezenet1_1()
@@ -328,3 +381,4 @@ if __name__ == '__main__':
     test_clip()
     test_matmul()
     test_gather()
+    test_lrn()