Fix crop op. (#12603)

* Fix infer shape of crop op.
* Speed crop op.

paddle/fluid/operators/crop_op.cc

-/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserved.
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -188,6 +188,7 @@ namespace ops = paddle::operators;
 REGISTER_OPERATOR(crop, ops::CropOp, ops::CropOpMaker,
                   paddle::framework::DefaultGradOpDescMaker<true>);
 REGISTER_OPERATOR(crop_grad, ops::CropOpGrad);
-REGISTER_OP_CPU_KERNEL(crop, ops::CropKernel<float>);
+REGISTER_OP_CPU_KERNEL(
+    crop, ops::CropKernel<paddle::platform::CPUDeviceContext, float>);
 REGISTER_OP_CPU_KERNEL(
     crop_grad, ops::CropGradKernel<paddle::platform::CPUDeviceContext, float>);

paddle/fluid/operators/crop_op.cu

-/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserved.
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@ limitations under the License. */
 #include "paddle/fluid/operators/crop_op.h"
 
 namespace ops = paddle::operators;
-REGISTER_OP_CUDA_KERNEL(crop, ops::CropKernel<float>);
+REGISTER_OP_CUDA_KERNEL(
+    crop, ops::CropKernel<paddle::platform::CUDADeviceContext, float>);
 REGISTER_OP_CUDA_KERNEL(
     crop_grad, ops::CropGradKernel<paddle::platform::CUDADeviceContext, float>);

paddle/fluid/operators/crop_op.h

-/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserved.
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -58,14 +58,15 @@ static std::vector<int> GetOffsets(const framework::ExecutionContext& ctx) {
   return res;
 }
 
-template <typename T>
-class CropKernel : public framework::OpKernel<T> {
- public:
-  void Compute(const framework::ExecutionContext& context) const override {
+template <typename DeviceContext, typename T, size_t D>
+void CropFunction(const framework::ExecutionContext& context) {
   auto* x = context.Input<Tensor>("X");
   auto* out = context.Output<Tensor>("Out");
-    const T* x_data = x->data<T>();
-    T* out_data = out->mutable_data<T>(context.GetPlace());
+  auto out_dims = out->dims();
+  if (out_dims[0] == -1) {
+    out_dims[0] = x->dims()[0];
+  }
+  out->mutable_data<T>(out_dims, context.GetPlace());
   auto x_stride = framework::stride(x->dims());
   auto out_stride = framework::stride(out->dims());
   auto offsets = GetOffsets(context);
@@ -73,17 +74,58 @@ class CropKernel : public framework::OpKernel<T> {
   for (size_t i = 0; i < offsets.size(); ++i) {
     offset += (x_stride[i] * offsets[i]);
   }
-    StridedMemcpy<T>(context.device_context(), x_data + offset, x_stride,
-                     out->dims(), out_stride, out_data);
+
+  auto x_tensor = EigenTensor<T, D>::From(*x);
+  auto out_tensor = EigenTensor<T, D>::From(*out);
+  Eigen::array<int, D> e_offsets;
+  Eigen::array<int, D> e_shape;
+  for (size_t i = 0; i < D; ++i) {
+    e_offsets[i] = offsets[i];
+    e_shape[i] = out->dims()[i];
+  }
+  auto& place =
+      *context.template device_context<DeviceContext>().eigen_device();
+  out_tensor.device(place) = x_tensor.slice(e_offsets, e_shape);
+}
+
+template <typename DeviceContext, typename T>
+class CropKernel : public framework::OpKernel<T> {
+ public:
+  void Compute(const framework::ExecutionContext& context) const override {
+    int rank = context.Input<Tensor>("X")->dims().size();
+    switch (rank) {
+      case 1:
+        CropFunction<DeviceContext, T, 1>(context);
+        break;
+      case 2:
+        CropFunction<DeviceContext, T, 2>(context);
+        break;
+      case 3:
+        CropFunction<DeviceContext, T, 3>(context);
+        break;
+      case 4:
+        CropFunction<DeviceContext, T, 4>(context);
+        break;
+      case 5:
+        CropFunction<DeviceContext, T, 5>(context);
+        break;
+      case 6:
+        CropFunction<DeviceContext, T, 6>(context);
+        break;
+      default:
+        PADDLE_THROW(
+            "CropOp only support tensors with no more than 6 dimensions.");
+    }
   }
 };
 
 template <typename DeviceContext, typename T, size_t D>
 void CropGradFunction(const framework::ExecutionContext& context) {
   auto* d_x = context.Output<Tensor>(framework::GradVarName("X"));
+  auto* x = context.Input<Tensor>("X");
   if (d_x != nullptr) {
     auto* d_out = context.Input<Tensor>(framework::GradVarName("Out"));
-    d_x->mutable_data<T>(context.GetPlace());
+    d_x->mutable_data<T>(x->dims(), context.GetPlace());
     auto offsets = GetOffsets(context);
     Eigen::array<std::pair<int, int>, D> paddings;
     for (size_t i = 0; i < D; ++i) {