From 8b30fadac3c0a9acec72937f330328dbbe1e9305 Mon Sep 17 00:00:00 2001
From: chengduoZH <zhaochengduo@163.com>
Date: Wed, 7 Mar 2018 10:21:47 +0800
Subject: [PATCH] refine elementwise sub,div,min,max

---
 paddle/fluid/operators/elementwise_div_op.h | 79 ++-------------------
 paddle/fluid/operators/elementwise_max_op.h | 79 +++------------------
 paddle/fluid/operators/elementwise_min_op.h | 79 +++------------------
 paddle/fluid/operators/elementwise_mul_op.h | 11 ++-
 paddle/fluid/operators/elementwise_sub_op.h | 63 ++--------------
 5 files changed, 34 insertions(+), 277 deletions(-)

diff --git a/paddle/fluid/operators/elementwise_div_op.h b/paddle/fluid/operators/elementwise_div_op.h
index 6bcc577456b13..95649ac46e6bd 100644
--- a/paddle/fluid/operators/elementwise_div_op.h
+++ b/paddle/fluid/operators/elementwise_div_op.h
@@ -41,77 +41,14 @@ class ElementwiseDivKernel : public framework::OpKernel<T> {
 };
 
 template <typename T>
-struct ElementwiseDivGradFunctor {
-  template <typename Device, typename X, typename Y, typename Z, typename dX,
-            typename dY, typename dZ>
-  void operator()(Device d, X x, Y y, Z z, dX dx, dY dy, dZ dz) {
-    auto y_e = framework::EigenVector<T>::Flatten(*y);
-    auto z_e = framework::EigenVector<T>::Flatten(*z);
-    auto dz_e = framework::EigenVector<T>::Flatten(*dz);
-
-    if (dx) {
-      auto dx_e = framework::EigenVector<T>::Flatten(*dx);
-      dx_e.device(d) = dz_e / y_e;
-    }
-
-    if (dy) {
-      auto dy_e = framework::EigenVector<T>::Flatten(*dy);
-      dy_e.device(d) = -1.0 * dz_e * z_e / y_e;
-    }
-  }
-};
-
-template <typename T>
-struct ElementwiseDivBroadCastGradFunctor {
-  template <typename Device, typename X, typename Y, typename Z, typename dX,
-            typename dY, typename dZ, typename Pre, typename N>
-  void operator()(Device d, X x, Y y, Z z, dX dx, dY dy, dZ dz, Pre pre, N n) {
-    auto x_e = framework::EigenVector<T>::Flatten(*x);
-    auto y_e = framework::EigenVector<T>::Flatten(*y);
-    auto dz_e = framework::EigenVector<T>::Flatten(*dz);
-
-    auto y_e_bcast = y_e.reshape(Eigen::DSizes<int, 2>(1, n))
-                         .broadcast(Eigen::DSizes<int, 2>(pre, 1))
-                         .reshape(Eigen::DSizes<int, 1>(x_e.size()));
-
-    if (dx) {
-      auto dx_e = framework::EigenVector<T>::Flatten(*dx);
-      dx_e.device(d) = dz_e / y_e_bcast;
-    }
-
-    if (dy) {
-      auto dy_e = framework::EigenVector<T>::Flatten(*dy);
-      dy_e.device(d) = (-1.0 * (x_e * dz_e) / (y_e_bcast * y_e_bcast))
-                           .reshape(Eigen::DSizes<int, 2>(pre, n))
-                           .sum(Eigen::array<int, 1>{{0}});
-    }
-  }
+struct DivGradDX {
+  HOSTDEVICE T operator()(T x, T y, T out, T dout) const { return dout / y; }
 };
 
 template <typename T>
-struct ElementwiseDivBroadCast2GradFunctor {
-  template <typename Device, typename X, typename Y, typename Z, typename dX,
-            typename dY, typename dZ, typename Pre, typename N, typename Post>
-  void operator()(Device d, X x, Y y, Z z, dX dx, dY dy, dZ dz, Pre pre, N n,
-                  Post post) {
-    auto x_e = framework::EigenVector<T>::Flatten(*x);
-    auto y_e = framework::EigenVector<T>::Flatten(*y);
-    auto dz_e = framework::EigenVector<T>::Flatten(*dz);
-
-    auto y_e_bcast = y_e.reshape(Eigen::DSizes<int, 3>(1, n, 1))
-                         .broadcast(Eigen::DSizes<int, 3>(pre, 1, post))
-                         .reshape(Eigen::DSizes<int, 1>(x_e.size()));
-    if (dx) {
-      auto dx_e = framework::EigenVector<T>::Flatten(*dx);
-      dx_e.device(d) = dz_e / y_e_bcast;
-    }
-
-    if (dy) {
-      auto dy_e = framework::EigenVector<T>::Flatten(*dy);
-      dy_e.device(d) = (-1.0 * (x_e * dz_e) / (y_e_bcast * y_e_bcast))
-                           .reshape(Eigen::DSizes<int, 3>(pre, n, post))
-                           .sum(Eigen::array<int, 2>{{0, 2}});
-    }
+struct DivGradDY {
+  HOSTDEVICE T operator()(T x, T y, T out, T dout) const {
+    return -dout * x / (y * y);
   }
 };
 
@@ -128,10 +65,8 @@ class ElementwiseDivGradKernel : public framework::OpKernel<T> {
     auto* dx = ctx.Output<Tensor>(framework::GradVarName("X"));
     auto* dy = ctx.Output<Tensor>(framework::GradVarName("Y"));
     int axis = ctx.Attr<int>("axis");
-    ElementwiseGradCompute<DeviceContext, T, ElementwiseDivGradFunctor<T>,
-                           ElementwiseDivBroadCastGradFunctor<T>,
-                           ElementwiseDivBroadCast2GradFunctor<T>>(
-        ctx, x, y, out, dout, axis, dx, dy);
+    ElemwiseGradCompute<DeviceContext, T, DivGradDX<T>, DivGradDY<T>>(
+        ctx, *x, *y, *out, *dout, axis, dx, dy, DivGradDX<T>(), DivGradDY<T>());
   }
 };
 
diff --git a/paddle/fluid/operators/elementwise_max_op.h b/paddle/fluid/operators/elementwise_max_op.h
index ab3a3d58275e8..527a18ee3ba88 100644
--- a/paddle/fluid/operators/elementwise_max_op.h
+++ b/paddle/fluid/operators/elementwise_max_op.h
@@ -41,76 +41,16 @@ class ElementwiseMaxKernel : public framework::OpKernel<T> {
 };
 
 template <typename T>
-struct ElementwiseMaxGradFunctor {
-  template <typename Device, typename X, typename Y, typename Z, typename dX,
-            typename dY, typename dZ>
-  void operator()(Device d, X x, Y y, Z z, dX dx, dY dy, dZ dz) {
-    auto x_e = framework::EigenVector<T>::Flatten(*x);
-    auto y_e = framework::EigenVector<T>::Flatten(*y);
-    auto dz_e = framework::EigenVector<T>::Flatten(*dz);
-
-    if (dx) {
-      auto dx_e = framework::EigenVector<T>::Flatten(*dx);
-      dx_e.device(d) = (x_e > y_e).template cast<T>() * dz_e;
-    }
-    if (dy) {
-      auto dy_e = framework::EigenVector<T>::Flatten(*dy);
-      dy_e.device(d) = (x_e <= y_e).template cast<T>() * dz_e;
-    }
+struct MaxGradDx {
+  HOSTDEVICE T operator()(T x, T y, T out, T dout) const {
+    return dout * (x > y);
   }
 };
 
 template <typename T>
-struct ElementwiseMaxBroadCastGradFunctor {
-  template <typename Device, typename X, typename Y, typename Z, typename dX,
-            typename dY, typename dZ, typename Pre, typename N>
-  void operator()(Device d, X x, Y y, Z z, dX dx, dY dy, dZ dz, Pre pre, N n) {
-    auto x_e = framework::EigenVector<T>::Flatten(*x);
-    auto y_e = framework::EigenVector<T>::Flatten(*y);
-    auto dz_e = framework::EigenVector<T>::Flatten(*dz);
-
-    auto y_e_bcast = y_e.reshape(Eigen::DSizes<int, 2>(1, n))
-                         .broadcast(Eigen::DSizes<int, 2>(pre, 1))
-                         .reshape(Eigen::DSizes<int, 1>(x_e.size()));
-
-    if (dx) {
-      auto dx_e = framework::EigenVector<T>::Flatten(*dx);
-      dx_e.device(d) = (x_e > y_e_bcast).template cast<T>() * dz_e;
-    }
-
-    if (dy) {
-      auto dy_e = framework::EigenVector<T>::Flatten(*dy);
-      dy_e.device(d) = ((x_e <= y_e_bcast).template cast<T>() * dz_e)
-                           .reshape(Eigen::DSizes<int, 2>(pre, n))
-                           .sum(Eigen::array<int, 1>{{0}});
-    }
-  }
-};
-
-template <typename T>
-struct ElementwiseMaxBroadCast2GradFunctor {
-  template <typename Device, typename X, typename Y, typename Z, typename dX,
-            typename dY, typename dZ, typename Pre, typename N, typename Post>
-  void operator()(Device d, X x, Y y, Z z, dX dx, dY dy, dZ dz, Pre pre, N n,
-                  Post post) {
-    auto x_e = framework::EigenVector<T>::Flatten(*x);
-    auto y_e = framework::EigenVector<T>::Flatten(*y);
-    auto dz_e = framework::EigenVector<T>::Flatten(*dz);
-
-    auto y_e_bcast = y_e.reshape(Eigen::DSizes<int, 3>(1, n, 1))
-                         .broadcast(Eigen::DSizes<int, 3>(pre, 1, post))
-                         .reshape(Eigen::DSizes<int, 1>(x_e.size()));
-    if (dx) {
-      auto dx_e = framework::EigenVector<T>::Flatten(*dx);
-      dx_e.device(d) = (x_e > y_e_bcast).template cast<T>() * dz_e;
-    }
-
-    if (dy) {
-      auto dy_e = framework::EigenVector<T>::Flatten(*dy);
-      dy_e.device(d) = ((x_e <= y_e_bcast).template cast<T>() * dz_e)
-                           .reshape(Eigen::DSizes<int, 3>(pre, n, post))
-                           .sum(Eigen::array<int, 2>{{0, 2}});
-    }
+struct MaxGradDy {
+  HOSTDEVICE T operator()(T x, T y, T out, T dout) const {
+    return dout * (x <= y);
   }
 };
 
@@ -127,12 +67,9 @@ class ElementwiseMaxGradKernel : public framework::OpKernel<T> {
     auto* dx = ctx.Output<Tensor>(framework::GradVarName("X"));
     auto* dy = ctx.Output<Tensor>(framework::GradVarName("Y"));
     int axis = ctx.Attr<int>("axis");
-    ElementwiseGradCompute<DeviceContext, T, ElementwiseMaxGradFunctor<T>,
-                           ElementwiseMaxBroadCastGradFunctor<T>,
-                           ElementwiseMaxBroadCast2GradFunctor<T>>(
-        ctx, x, y, out, dout, axis, dx, dy);
+    ElemwiseGradCompute<DeviceContext, T, MaxGradDx<T>, MaxGradDy<T>>(
+        ctx, *x, *y, *out, *dout, axis, dx, dy, MaxGradDx<T>(), MaxGradDy<T>());
   }
 };
-
 }  // namespace operators
 }  // namespace paddle
diff --git a/paddle/fluid/operators/elementwise_min_op.h b/paddle/fluid/operators/elementwise_min_op.h
index f0eec9d2468b5..d4e5831463f3e 100644
--- a/paddle/fluid/operators/elementwise_min_op.h
+++ b/paddle/fluid/operators/elementwise_min_op.h
@@ -41,76 +41,16 @@ class ElementwiseMinKernel : public framework::OpKernel<T> {
 };
 
 template <typename T>
-struct ElementwiseMinGradFunctor {
-  template <typename Device, typename X, typename Y, typename Z, typename dX,
-            typename dY, typename dZ>
-  void operator()(Device d, X x, Y y, Z z, dX dx, dY dy, dZ dz) {
-    auto x_e = framework::EigenVector<T>::Flatten(*x);
-    auto y_e = framework::EigenVector<T>::Flatten(*y);
-    auto dz_e = framework::EigenVector<T>::Flatten(*dz);
-
-    if (dx) {
-      auto dx_e = framework::EigenVector<T>::Flatten(*dx);
-      dx_e.device(d) = (x_e < y_e).template cast<T>() * dz_e;
-    }
-    if (dy) {
-      auto dy_e = framework::EigenVector<T>::Flatten(*dy);
-      dy_e.device(d) = (x_e >= y_e).template cast<T>() * dz_e;
-    }
+struct MinGradDx {
+  HOSTDEVICE T operator()(T x, T y, T out, T dout) const {
+    return dout * (x < y);
   }
 };
 
 template <typename T>
-struct ElementwiseMinBroadCastGradFunctor {
-  template <typename Device, typename X, typename Y, typename Z, typename dX,
-            typename dY, typename dZ, typename Pre, typename N>
-  void operator()(Device d, X x, Y y, Z z, dX dx, dY dy, dZ dz, Pre pre, N n) {
-    auto x_e = framework::EigenVector<T>::Flatten(*x);
-    auto y_e = framework::EigenVector<T>::Flatten(*y);
-    auto dz_e = framework::EigenVector<T>::Flatten(*dz);
-
-    auto y_e_bcast = y_e.reshape(Eigen::DSizes<int, 2>(1, n))
-                         .broadcast(Eigen::DSizes<int, 2>(pre, 1))
-                         .reshape(Eigen::DSizes<int, 1>(x_e.size()));
-
-    if (dx) {
-      auto dx_e = framework::EigenVector<T>::Flatten(*dx);
-      dx_e.device(d) = (x_e < y_e_bcast).template cast<T>() * dz_e;
-    }
-
-    if (dy) {
-      auto dy_e = framework::EigenVector<T>::Flatten(*dy);
-      dy_e.device(d) = ((x_e >= y_e_bcast).template cast<T>() * dz_e)
-                           .reshape(Eigen::DSizes<int, 2>(pre, n))
-                           .sum(Eigen::array<int, 1>{{0}});
-    }
-  }
-};
-
-template <typename T>
-struct ElementwiseMinBroadCast2GradFunctor {
-  template <typename Device, typename X, typename Y, typename Z, typename dX,
-            typename dY, typename dZ, typename Pre, typename N, typename Post>
-  void operator()(Device d, X x, Y y, Z z, dX dx, dY dy, dZ dz, Pre pre, N n,
-                  Post post) {
-    auto x_e = framework::EigenVector<T>::Flatten(*x);
-    auto y_e = framework::EigenVector<T>::Flatten(*y);
-    auto dz_e = framework::EigenVector<T>::Flatten(*dz);
-
-    auto y_e_bcast = y_e.reshape(Eigen::DSizes<int, 3>(1, n, 1))
-                         .broadcast(Eigen::DSizes<int, 3>(pre, 1, post))
-                         .reshape(Eigen::DSizes<int, 1>(x_e.size()));
-    if (dx) {
-      auto dx_e = framework::EigenVector<T>::Flatten(*dx);
-      dx_e.device(d) = (x_e < y_e_bcast).template cast<T>() * dz_e;
-    }
-
-    if (dy) {
-      auto dy_e = framework::EigenVector<T>::Flatten(*dy);
-      dy_e.device(d) = ((x_e >= y_e_bcast).template cast<T>() * dz_e)
-                           .reshape(Eigen::DSizes<int, 3>(pre, n, post))
-                           .sum(Eigen::array<int, 2>{{0, 2}});
-    }
+struct MinGradDy {
+  HOSTDEVICE T operator()(T x, T y, T out, T dout) const {
+    return dout * (x >= y);
   }
 };
 
@@ -127,12 +67,9 @@ class ElementwiseMinGradKernel : public framework::OpKernel<T> {
     auto* dx = ctx.Output<Tensor>(framework::GradVarName("X"));
     auto* dy = ctx.Output<Tensor>(framework::GradVarName("Y"));
     int axis = ctx.Attr<int>("axis");
-    ElementwiseGradCompute<DeviceContext, T, ElementwiseMinGradFunctor<T>,
-                           ElementwiseMinBroadCastGradFunctor<T>,
-                           ElementwiseMinBroadCast2GradFunctor<T>>(
-        ctx, x, y, out, dout, axis, dx, dy);
+    ElemwiseGradCompute<DeviceContext, T, MinGradDx<T>, MinGradDy<T>>(
+        ctx, *x, *y, *out, *dout, axis, dx, dy, MinGradDx<T>(), MinGradDy<T>());
   }
 };
-
 }  // namespace operators
 }  // namespace paddle
diff --git a/paddle/fluid/operators/elementwise_mul_op.h b/paddle/fluid/operators/elementwise_mul_op.h
index e2b59b3112096..dc73cb6f23614 100644
--- a/paddle/fluid/operators/elementwise_mul_op.h
+++ b/paddle/fluid/operators/elementwise_mul_op.h
@@ -40,14 +40,15 @@ class ElementwiseMulKernel : public framework::OpKernel<T> {
 };
 
 template <typename T>
-struct IdentityGrad_DX {
+struct MulGradDX {
   HOSTDEVICE T operator()(T x, T y, T out, T dout) const { return dout * y; }
 };
 
 template <typename T>
-struct IdentityGrad_DY {
+struct MulGradDY {
   HOSTDEVICE T operator()(T x, T y, T out, T dout) const { return dout * x; }
 };
+
 template <typename DeviceContext, typename T>
 class ElementwiseMulGradKernel : public framework::OpKernel<T> {
  public:
@@ -61,10 +62,8 @@ class ElementwiseMulGradKernel : public framework::OpKernel<T> {
     auto* dx = ctx.Output<Tensor>(framework::GradVarName("X"));
     auto* dy = ctx.Output<Tensor>(framework::GradVarName("Y"));
     int axis = ctx.Attr<int>("axis");
-    ElemwiseGradCompute<DeviceContext, T, IdentityGrad_DX<T>,
-                        IdentityGrad_DY<T>>(ctx, *x, *y, *out, *dout, axis, dx,
-                                            dy, IdentityGrad_DX<T>(),
-                                            IdentityGrad_DY<T>());
+    ElemwiseGradCompute<DeviceContext, T, MulGradDX<T>, MulGradDY<T>>(
+        ctx, *x, *y, *out, *dout, axis, dx, dy, MulGradDX<T>(), MulGradDY<T>());
   }
 };
 }  // namespace operators
diff --git a/paddle/fluid/operators/elementwise_sub_op.h b/paddle/fluid/operators/elementwise_sub_op.h
index a8fc242ed79ec..fe088b8203722 100644
--- a/paddle/fluid/operators/elementwise_sub_op.h
+++ b/paddle/fluid/operators/elementwise_sub_op.h
@@ -40,61 +40,13 @@ class ElementwiseSubKernel : public framework::OpKernel<T> {
 };
 
 template <typename T>
-struct ElementwiseSubGradFunctor {
-  template <typename Device, typename X, typename Y, typename Z, typename dX,
-            typename dY, typename dZ>
-  void operator()(Device d, X x, Y y, Z z, dX dx, dY dy, dZ dz) {
-    auto dz_e = framework::EigenVector<T>::Flatten(*dz);
-    if (dx) {
-      auto dx_e = framework::EigenVector<T>::Flatten(*dx);
-      dx_e.device(d) = dz_e;
-    }
-    if (dy) {
-      auto dy_e = framework::EigenVector<T>::Flatten(*dy);
-      dy_e.device(d) = (-1.0) * dz_e;
-    }
-  }
+struct SubGradDX {
+  HOSTDEVICE T operator()(T x, T y, T out, T dout) const { return dout; }
 };
 
 template <typename T>
-struct ElementwiseSubBroadCastGradFunctor {
-  template <typename Device, typename X, typename Y, typename Z, typename dX,
-            typename dY, typename dZ, typename Pre, typename N>
-  void operator()(Device d, X x, Y y, Z z, dX dx, dY dy, dZ dz, Pre pre, N n) {
-    auto dz_e = framework::EigenVector<T>::Flatten(*dz);
-    if (dx) {
-      auto dx_e = framework::EigenVector<T>::Flatten(*dx);
-      dx_e.device(d) = dz_e;
-    }
-
-    if (dy) {
-      auto dy_e = framework::EigenVector<T>::Flatten(*dy);
-      dy_e.device(d) = (-1.0) *
-                       dz_e.reshape(Eigen::DSizes<int, 2>(pre, n))
-                           .sum(Eigen::array<int, 1>{{0}});
-    }
-  }
-};
-
-template <typename T>
-struct ElementwiseSubBroadCast2GradFunctor {
-  template <typename Device, typename X, typename Y, typename Z, typename dX,
-            typename dY, typename dZ, typename Pre, typename N, typename Post>
-  void operator()(Device d, X x, Y y, Z z, dX dx, dY dy, dZ dz, Pre pre, N n,
-                  Post post) {
-    auto dz_e = framework::EigenVector<T>::Flatten(*dz);
-    if (dx) {
-      auto dx_e = framework::EigenVector<T>::Flatten(*dx);
-      dx_e.device(d) = dz_e;
-    }
-
-    if (dy) {
-      auto dy_e = framework::EigenVector<T>::Flatten(*dy);
-      dy_e.device(d) = (-1.0) *
-                       dz_e.reshape(Eigen::DSizes<int, 3>(pre, n, post))
-                           .sum(Eigen::array<int, 2>{{0, 2}});
-    }
-  }
+struct SubGradDY {
+  HOSTDEVICE T operator()(T x, T y, T out, T dout) const { return -dout; }
 };
 
 template <typename DeviceContext, typename T>
@@ -110,12 +62,9 @@ class ElementwiseSubGradKernel : public framework::OpKernel<T> {
     auto* dx = ctx.Output<Tensor>(framework::GradVarName("X"));
     auto* dy = ctx.Output<Tensor>(framework::GradVarName("Y"));
     int axis = ctx.Attr<int>("axis");
-    ElementwiseGradCompute<DeviceContext, T, ElementwiseSubGradFunctor<T>,
-                           ElementwiseSubBroadCastGradFunctor<T>,
-                           ElementwiseSubBroadCast2GradFunctor<T>>(
-        ctx, x, y, out, dout, axis, dx, dy);
+    ElemwiseGradCompute<DeviceContext, T, SubGradDX<T>, SubGradDY<T>>(
+        ctx, *x, *y, *out, *dout, axis, dx, dy, SubGradDX<T>(), SubGradDY<T>());
   }
 };
-
 }  // namespace operators
 }  // namespace paddle