Add GPU sqrt functions

diff --git a/include/caffe/util/math_functions.hpp b/include/caffe/util/math_functions.hpp
index 37abce5..60a8404 100644 (file)
--- a/include/caffe/util/math_functions.hpp
+++ b/include/caffe/util/math_functions.hpp
@@ -214,6 +214,9 @@ void caffe_gpu_log(const int n, const Dtype* a, Dtype* y);
 template <typename Dtype>
 void caffe_gpu_powx(const int n, const Dtype* a, const Dtype b, Dtype* y);
 
+template <typename Dtype>
+void caffe_gpu_sqrt(const int n, const Dtype* a, Dtype* y);
+
 // caffe_gpu_rng_uniform with two arguments generates integers in the range
 // [0, UINT_MAX].
 void caffe_gpu_rng_uniform(const int n, unsigned int* r);

diff --git a/src/caffe/util/math_functions.cu b/src/caffe/util/math_functions.cu
index 6d00102..314e6ba 100644 (file)
--- a/src/caffe/util/math_functions.cu
+++ b/src/caffe/util/math_functions.cu
@@ -387,6 +387,27 @@ void caffe_gpu_powx<double>(const int N, const double* a,
       N, a, alpha, y);
 }
 
+template <typename Dtype>
+__global__ void sqrt_kernel(const int n, const Dtype* a, Dtype* y) {
+  CUDA_KERNEL_LOOP(index, n) {
+    y[index] = sqrt(a[index]);
+  }
+}
+
+template <>
+void caffe_gpu_sqrt<float>(const int N, const float* a, float* y) {
+  // NOLINT_NEXT_LINE(whitespace/operators)
+  sqrt_kernel<float><<<CAFFE_GET_BLOCKS(N), CAFFE_CUDA_NUM_THREADS>>>(
+      N, a, y);
+}
+
+template <>
+void caffe_gpu_sqrt<double>(const int N, const double* a, double* y) {
+  // NOLINT_NEXT_LINE(whitespace/operators)
+  sqrt_kernel<double><<<CAFFE_GET_BLOCKS(N), CAFFE_CUDA_NUM_THREADS>>>(
+      N, a, y);
+}
+
 DEFINE_AND_INSTANTIATE_GPU_UNARY_FUNC(sign, y[index] = (Dtype(0) < x[index])
                                       - (x[index] < Dtype(0)));
 DEFINE_AND_INSTANTIATE_GPU_UNARY_FUNC(sgnbit, y[index] = signbit(x[index]));