From fbbfe8b8594960934529330dc1321e1fdc6c2a6d Mon Sep 17 00:00:00 2001
From: chengduoZH <zhaochengduo@163.com>
Date: Mon, 4 Dec 2017 14:21:13 +0800
Subject: [PATCH] code refine

---
 paddle/operators/elementwise_add_op.h      |  39 +++++++-
 paddle/operators/elementwise_op_function.h | 108 +++++++++++++++++++++
 2 files changed, 146 insertions(+), 1 deletion(-)

diff --git a/paddle/operators/elementwise_add_op.h b/paddle/operators/elementwise_add_op.h
index f04fe3ec6..686d45573 100644
--- a/paddle/operators/elementwise_add_op.h
+++ b/paddle/operators/elementwise_add_op.h
@@ -19,11 +19,48 @@
 namespace paddle {
 namespace operators {
 
+template <typename T>
+struct AddFunctor {
+  HOSTDEVICE T operator()(T a, T b) const { return a + b; }
+};
+
 template <typename Place, typename T>
 class ElementwiseAddKernel : public framework::OpKernel<T> {
  public:
   void Compute(const framework::ExecutionContext& ctx) const override {
-    ElementwiseCompute<EigenAddFunctor, Place, T>(ctx);
+    using Tensor = framework::Tensor;
+
+    auto* x = ctx.Input<Tensor>("X");
+    auto* y = ctx.Input<Tensor>("Y");
+    auto* z = ctx.Output<Tensor>("Out");
+    z->mutable_data<T>(ctx.GetPlace());
+    TransformFunctor<AddFunctor<T>, T, Place> functor(x, y, z, ctx,
+                                                      AddFunctor<T>());
+
+    auto x_dims = x->dims();
+    auto y_dims = y->dims();
+    PADDLE_ENFORCE_GE(x_dims.size(), y_dims.size(),
+                      "Rank of first input must >= rank of second input.");
+
+    if (x_dims == y_dims) {
+      functor.Run();
+      return;
+    }
+
+    int axis = ctx.Attr<int>("axis");
+    axis = (axis == -1 ? x_dims.size() - y_dims.size() : axis);
+    PADDLE_ENFORCE(axis >= 0 && axis < x_dims.size(),
+                   "Axis should be in range [0, x_dims)");
+
+    int pre, n, post;
+    get_mid_dims(x_dims, y_dims, axis, pre, n, post);
+    if (post == 1) {
+      functor.RunRowWise(n, pre);
+      return;
+    } else {
+      functor.RunMidWise(n, pre, post);
+      return;
+    }
   }
 };
 
diff --git a/paddle/operators/elementwise_op_function.h b/paddle/operators/elementwise_op_function.h
index 8aa35b2c4..22b96b931 100644
--- a/paddle/operators/elementwise_op_function.h
+++ b/paddle/operators/elementwise_op_function.h
@@ -16,6 +16,7 @@
 #include "paddle/framework/eigen.h"
 #include "paddle/framework/op_registry.h"
 #include "paddle/framework/operator.h"
+#include "paddle/platform/transform.h"
 
 #include "paddle/operators/math/math_function.h"
 
@@ -54,6 +55,113 @@ inline void get_mid_dims(const framework::DDim& x_dims,
   }
 }
 
+template <typename T, typename Place>
+struct RowwiseTransformIterator;
+template <typename T, typename Place>
+struct MidWiseTransformIterator;
+
+template <typename T>
+struct RowwiseTransformIterator<T, platform::CPUPlace> {
+  RowwiseTransformIterator(const T* ptr, int n) : ptr_(ptr), i_(0), n_(n) {}
+
+  RowwiseTransformIterator<T, platform::CPUPlace>& operator++() {
+    ++i_;
+    if (i_ == n_) {
+      i_ = 0;
+    }
+    return *this;
+  }
+
+  bool operator==(
+      const RowwiseTransformIterator<T, platform::CPUPlace>& rhs) const {
+    return &(this->operator*()) == &(*rhs);
+  }
+
+  bool operator!=(
+      const RowwiseTransformIterator<T, platform::CPUPlace>& rhs) const {
+    return &(this->operator*()) &= &(*rhs);
+  }
+
+  const T& operator*() { return ptr_[i_]; }
+
+  const T* ptr_;
+  int i_;
+  int n_;
+};
+
+template <typename T>
+struct MidWiseTransformIterator<T, platform::CPUPlace> {
+  MidWiseTransformIterator(const T* ptr, int n, int post)
+      : ptr_(ptr), i_(0), j_(0), n_(n), post_(post) {}
+
+  MidWiseTransformIterator<T, platform::CPUPlace>& operator++() {
+    ++j_;
+    if (j_ == post_) {
+      j_ = 0;
+      ++i_;
+      if (i_ == n_) {
+        i_ = 0;
+      }
+    }
+    return *this;
+  }
+
+  bool operator==(
+      const MidWiseTransformIterator<T, platform::CPUPlace>& rhs) const {
+    return &(this->operator*()) == &(*rhs);
+  }
+
+  bool operator!=(
+      const MidWiseTransformIterator<T, platform::CPUPlace>& rhs) const {
+    return &(this->operator*()) &= &(*rhs);
+  }
+
+  const T& operator*() { return ptr_[i_]; }
+
+  const T* ptr_;
+  int i_;
+  int j_;
+  int n_;
+  int post_;
+};
+
+template <typename Functor, typename T, typename Place>
+struct TransformFunctor {
+  TransformFunctor(const framework::Tensor* x, const framework::Tensor* y,
+                   framework::Tensor* z, const framework::ExecutionContext& ctx,
+                   Functor func)
+      : x_(x->data<T>()),
+        y_(y->data<T>()),
+        z_(z->mutable_data<T>(ctx.GetPlace())),
+        nx_(x->numel()),
+        ctx_(ctx),
+        func_(func) {}
+
+  inline void Run() const {
+    platform::Transform<Place> trans;
+    trans(ctx_.device_context(), x_, x_ + nx_, y_, z_, func_);
+  }
+
+  inline void RunRowWise(int n, int pre) const {
+    platform::Transform<Place> trans;
+    trans(ctx_.device_context(), x_, x_ + nx_,
+          RowwiseTransformIterator<T, Place>(y_, n), z_, func_);
+  }
+
+  inline void RunMidWise(int n, int pre, int post) const {
+    platform::Transform<Place> trans;
+    trans(ctx_.device_context(), x_, x_ + nx_,
+          MidWiseTransformIterator<T, Place>(y_, n, post), z_, func_);
+  }
+
+  const T* x_;
+  const T* y_;
+  T* z_;
+  int64_t nx_;
+  const framework::ExecutionContext& ctx_;
+  Functor func_;
+};
+
 #define EIGEN_FUNCTOR(name, eigen_op)                                          \
   struct Eigen##name##Functor {                                                \
     template <typename Place, typename T>                                      \
-- 
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