From 32d881beabdfb7130072bb624bc29fa6c6b30904 Mon Sep 17 00:00:00 2001
From: qingqing01 <dangqingqing@baidu.com>
Date: Tue, 26 Dec 2017 05:46:23 -0800
Subject: [PATCH] Optimize the rowwise add function.

---
 paddle/operators/math/math_function.cc     | 32 ++++++++++++++++++++++
 paddle/operators/math/math_function.cu     | 27 ++++++++++++++++++
 paddle/operators/math/math_function_impl.h | 19 -------------
 3 files changed, 59 insertions(+), 19 deletions(-)

diff --git a/paddle/operators/math/math_function.cc b/paddle/operators/math/math_function.cc
index 2b35e4532a..1a4829c49f 100644
--- a/paddle/operators/math/math_function.cc
+++ b/paddle/operators/math/math_function.cc
@@ -302,8 +302,40 @@ void set_constant(const platform::DeviceContext& context,
 #endif
 }
 
+template <typename T>
+struct RowwiseAdd<platform::CPUDeviceContext, T> {
+  void operator()(const platform::CPUDeviceContext& context,
+                  const framework::Tensor& input,
+                  const framework::Tensor& vector, framework::Tensor* output) {
+    auto in_dims = input.dims();
+    auto size = input.numel() / in_dims[0];
+    PADDLE_ENFORCE_EQ(vector.numel(), size);
+    PADDLE_ENFORCE_EQ(output->dims(), in_dims);
+
+    // auto in = framework::EigenMatrix<T>::From(input);
+    // auto vec = framework::EigenVector<T>::Flatten(vector);
+    // auto out = framework::EigenMatrix<T>::From(*output);
+    // for (int64_t i = 0; i < in_dims[0]; ++i) {
+    //   out.chip(i, 0) = in.chip(i, 0) + vec;
+    // }
+
+    auto* in = input.data<T>();
+    auto* vec = vector.data<T>();
+    auto* out = output->data<T>();
+
+    int64_t h = in_dims[0];
+    int64_t w = in_dims[1];
+    for (int64_t i = 0; i < h; ++i) {
+      for (int64_t j = 0; j < w; ++j) {
+        out[i * w + j] = in[i * w + j] + vec[j];
+      }
+    }
+  }
+};
+
 template struct RowwiseAdd<platform::CPUDeviceContext, float>;
 template struct RowwiseAdd<platform::CPUDeviceContext, double>;
+
 template struct ColwiseSum<platform::CPUDeviceContext, float>;
 template struct ColwiseSum<platform::CPUDeviceContext, double>;
 
diff --git a/paddle/operators/math/math_function.cu b/paddle/operators/math/math_function.cu
index 927838a094..36e6cc8914 100644
--- a/paddle/operators/math/math_function.cu
+++ b/paddle/operators/math/math_function.cu
@@ -273,6 +273,33 @@ void set_constant_with_place<platform::CUDAPlace>(
                            TensorSetConstantGPU(context, tensor, value));
 }
 
+template <typename T>
+__global__ void RowwiseAddKernel(const T* a, const T* b, T* c, int64_t height,
+                                 int64_t width) {
+  int64_t num = height * width;
+  for (int i = blockIdx.x * blockDim.x + threadIdx.x; i < num;
+       i += blockDim.x * gridDim.x) {
+    int h = i / width;
+    int w = i % width;
+    int idx = h * width + w;
+    c[idx] = a[idx] + b[w];
+  }
+}
+
+template <typename T>
+struct RowwiseAdd<platform::CUDADeviceContext, T> {
+  void operator()(const platform::CUDADeviceContext& context,
+                  const framework::Tensor& input,
+                  const framework::Tensor& vector, framework::Tensor* output) {
+    auto in_dims = input.dims();
+    int blocks = 512;
+    int grids = (input.numel() + blocks - 1) / blocks;
+    RowwiseAddKernel<T><<<grids, blocks, 0, context.stream()>>>(
+        input.data<T>(), vector.data<T>(), output->data<T>(), in_dims[0],
+        in_dims[1]);
+  }
+};
+
 template struct RowwiseAdd<platform::CUDADeviceContext, float>;
 template struct RowwiseAdd<platform::CUDADeviceContext, double>;
 template struct ColwiseSum<platform::CUDADeviceContext, float>;
diff --git a/paddle/operators/math/math_function_impl.h b/paddle/operators/math/math_function_impl.h
index ddd798dace..de591626df 100644
--- a/paddle/operators/math/math_function_impl.h
+++ b/paddle/operators/math/math_function_impl.h
@@ -45,25 +45,6 @@ void Transpose<DeviceContext, T, Rank>::operator()(
   eigen_out.device(*dev) = eigen_in.shuffle(permute);
 }
 
-template <typename DeviceContext, typename T>
-void RowwiseAdd<DeviceContext, T>::operator()(const DeviceContext& context,
-                                              const framework::Tensor& input,
-                                              const framework::Tensor& vector,
-                                              framework::Tensor* output) {
-  auto in_dims = input.dims();
-  auto size = input.numel() / in_dims[0];
-  PADDLE_ENFORCE_EQ(vector.numel(), size);
-  PADDLE_ENFORCE_EQ(output->dims(), in_dims);
-
-  auto in = framework::EigenMatrix<T>::From(input);
-  auto vec = framework::EigenMatrix<T>::From(vector);
-  auto out = framework::EigenMatrix<T>::From(*output);
-  Eigen::array<int, 2> shape({{1, static_cast<int>(size)}});
-  Eigen::array<int, 2> bcast({{static_cast<int>(in_dims[0]), 1}});
-  out.device(*context.eigen_device()) =
-      in + vec.reshape(shape).broadcast(bcast);
-}
-
 template <typename DeviceContext, typename T>
 void ColwiseSum<DeviceContext, T>::operator()(const DeviceContext& context,
                                               const framework::Tensor& input,
-- 
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