follow comments

paddle/operators/elementwise_op_function.h

@@ -60,12 +60,13 @@ inline void get_mid_dims(const framework::DDim& x_dims,
 }
 
 template <typename T, typename Place>
-struct RowwiseTransformIterator;
+class RowwiseTransformIterator;
 template <typename T, typename Place>
-struct MidWiseTransformIterator;
+class MidWiseTransformIterator;
 
 template <typename T>
-struct RowwiseTransformIterator<T, platform::CPUPlace> {
+class RowwiseTransformIterator<T, platform::CPUPlace> {
+ public:
   RowwiseTransformIterator(const T* ptr, int n) : ptr_(ptr), i_(0), n_(n) {}
 
   RowwiseTransformIterator<T, platform::CPUPlace>& operator++() {
@@ -86,13 +87,15 @@ struct RowwiseTransformIterator<T, platform::CPUPlace> {
 
   const T& operator*() { return ptr_[i_]; }
 
+ private:
   const T* ptr_;
   int i_;
   int64_t n_;
 };
 
 template <typename T>
-struct MidWiseTransformIterator<T, platform::CPUPlace> {
+class MidWiseTransformIterator<T, platform::CPUPlace> {
+ public:
   MidWiseTransformIterator(const T* ptr, int n, int post)
       : ptr_(ptr), i_(0), j_(0), n_(n), post_(post) {}
 
@@ -113,6 +116,7 @@ struct MidWiseTransformIterator<T, platform::CPUPlace> {
 
   const T& operator*() { return ptr_[i_]; }
 
+ private:
   const T* ptr_;
   int i_;
   int64_t j_;
@@ -122,7 +126,7 @@ struct MidWiseTransformIterator<T, platform::CPUPlace> {
 
 #ifdef __NVCC__
 template <typename T>
-struct RowwiseTransformIterator<T, platform::GPUPlace>
+class RowwiseTransformIterator<T, platform::GPUPlace>
     : public thrust::iterator_adaptor<
           RowwiseTransformIterator<T, platform::GPUPlace>, const T*> {
  public:
@@ -142,7 +146,7 @@ struct RowwiseTransformIterator<T, platform::GPUPlace>
 };
 
 template <typename T>
-struct MidWiseTransformIterator<T, platform::GPUPlace>
+class MidWiseTransformIterator<T, platform::GPUPlace>
     : public thrust::iterator_adaptor<
           MidWiseTransformIterator<T, platform::GPUPlace>, const T*> {
  public:
@@ -164,7 +168,8 @@ struct MidWiseTransformIterator<T, platform::GPUPlace>
 #endif
 
 template <typename Functor, typename T, typename Place>
-struct TransformFunctor {
+class TransformFunctor {
+ public:
   TransformFunctor(const framework::Tensor* x, const framework::Tensor* y,
                    framework::Tensor* z, const platform::DeviceContext& ctx,
                    Functor func)
@@ -192,6 +197,7 @@ struct TransformFunctor {
           z_, func_);
   }
 
+ private:
   const T* x_;
   const T* y_;
   T* z_;