Add and test sum of absolute values math functions for CPU and GPU

include/caffe/util/math_functions.hpp

@@ -112,6 +112,13 @@ void caffe_gpu_dot(const int n, const Dtype* x, const Dtype* y, Dtype* out);
 template <typename Dtype>
 int caffe_hamming_distance(const int n, const Dtype* x, const Dtype* y);
 
+// Returns the sum of the absolute values of the elements of vector x
+template <typename Dtype>
+Dtype caffe_cpu_asum(const int n, const Dtype* x);
+
+template <typename Dtype>
+void caffe_gpu_asum(const int n, const Dtype* x, Dtype* y);
+
 }  // namespace caffe
 
 

src/caffe/test/test_math_functions.cpp

@@ -1,6 +1,7 @@
 // Copyright 2014 kloudkl@github
 
 #include <stdint.h>  // for uint32_t & uint64_t
+#include <cmath>  // for std::fabs
 
 #include "gtest/gtest.h"
 #include "caffe/blob.hpp"
@@ -74,4 +75,27 @@ TYPED_TEST(MathFunctionsTest, TestHammingDistance) {
            caffe_hamming_distance<TypeParam>(n, x, y));
 }
 
+TYPED_TEST(MathFunctionsTest, TestAsumCPU){
+  int n = this->blob_bottom_->count();
+  const TypeParam* x = this->blob_bottom_->cpu_data();
+  TypeParam std_asum = 0;
+  for (int i = 0; i < n; ++i) {
+    std_asum += std::fabs(x[i]);
+  }
+  TypeParam cpu_asum = caffe_cpu_asum<TypeParam>(n, x);
+  CHECK_LT((cpu_asum - std_asum) / std_asum, 1e-2);
+}
+
+TYPED_TEST(MathFunctionsTest, TestAsumGPU){
+  int n = this->blob_bottom_->count();
+  const TypeParam* x = this->blob_bottom_->cpu_data();
+  TypeParam std_asum = 0;
+  for (int i = 0; i < n; ++i) {
+    std_asum += std::fabs(x[i]);
+  }
+  TypeParam gpu_asum;
+  caffe_gpu_asum<TypeParam>(n, this->blob_bottom_->gpu_data(), &gpu_asum);
+  CHECK_LT((gpu_asum - std_asum) / std_asum, 1e-2);
+}
+
 }  // namespace caffe

src/caffe/util/math_functions.cpp

@@ -390,4 +390,24 @@ int caffe_hamming_distance<double>(const int n, const double* x,
   return dist;
 }
 
+template <>
+float caffe_cpu_asum<float>(const int n, const float* x) {
+  return cblas_sasum(n, x, 1);
+}
+
+template <>
+double caffe_cpu_asum<double>(const int n, const double* x) {
+  return cblas_dasum(n, x, 1);
+}
+
+template <>
+void caffe_gpu_asum<float>(const int n, const float* x, float* y) {
+  CUBLAS_CHECK(cublasSasum(Caffe::cublas_handle(), n, x, 1, y));
+}
+
+template <>
+void caffe_gpu_asum<double>(const int n, const double* x, double* y) {
+  CUBLAS_CHECK(cublasDasum(Caffe::cublas_handle(), n, x, 1, y));
+}
+
 }  // namespace caffe