/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. */

#include "ConvOp.h"
#include "DepthwiseConvOp.h"
#include "GemmFunctor.h"
#include "paddle/math/MemoryHandle.h"

namespace paddle {
template <class T>
__global__ 
void ConvolutionDepthwiseForward(const int nthreads,
    const T* const inputData, const T* const filterData,
    const int batchSize, const int outputChannels, const int outputHeight,
    const int outputWidth, const int inputHeight, const int inputWidth,
    const int filterHeight, const int filterWidth, const int strideH,
    const int strideW, const int paddingH, const int paddingW,
    T* const outputData) {

  int index =
    (blockIdx.x * gridDim.y + blockIdx.y) * blockDim.x + threadIdx.x;
  
  if(index < nthreads) {
    const int n = index / outputChannels / outputHeight / outputWidth;
    const int c = (index / outputHeight / outputWidth) % outputChannels;
    const int h = (index / outputWidth) % outputHeight;
    const int w = index % outputWidth;
    const T* weight = filterData + c * filterHeight * filterWidth;
    T value = 0;
	const int h_in_start = -paddingH + h * strideH;
	const int w_in_start = -paddingW + w * strideW;
	const int h_in_end = -paddingH + h * strideH + filterHeight - 1;
	const int w_in_end = -paddingW + w * strideW + filterWidth - 1;
    if ((h_in_start >= 0) && (h_in_end < inputHeight) 
		 &&(w_in_start >= 0) && (w_in_end < inputWidth)) {
		for (int kh = 0; kh < filterHeight; ++kh) {
		  for (int kw = 0; kw < filterWidth; ++kw) {
			const int h_in = -paddingH + h * strideH + kh;
			const int w_in = -paddingW + w * strideW + kw;
			  const int offset = ((n * outputChannels + c) * inputHeight + h_in)
					* inputWidth + w_in;
			  value += (*weight) * inputData[offset];
			++weight;
		  }
		}
	}else{
		for (int kh = 0; kh < filterHeight; ++kh) {
		  for (int kw = 0; kw < filterWidth; ++kw) {
			const int h_in = -paddingH + h * strideH + kh;
			const int w_in = -paddingW + w * strideW + kw;
			if ((h_in >= 0) && (h_in < inputHeight)
				  && (w_in >= 0) && (w_in < inputWidth)) {
			  const int offset = ((n * outputChannels + c) * inputHeight + h_in)
					* inputWidth + w_in;
			  value += (*weight) * inputData[offset];
			}
			++weight;
		  }
		}
	}
    outputData[index] = value;
  }
}

template <class T>
__global__
void ConvolutionDepthwiseInputBackward(const int nthreads,
    const T* const top_diff, const T* const weight_data,
    const int num, const int outputChannels, const int outputHeight,
    const int outputWidth, const int inputHeight, const int inputWidth,
    const int filterHeight, const int filterWidth, const int strideH,
    const int strideW, const int paddingH, const int paddingW,
     T* const bottom_diff) {
  int index =
    (blockIdx.x * gridDim.y + blockIdx.y) * blockDim.x + threadIdx.x;
  if(index < nthreads) {
    const int n = index / outputChannels / inputHeight / inputWidth;
    const int c = (index / inputHeight / inputWidth) % outputChannels;
    const int h = (index / inputWidth) % inputHeight;
    const int w = index % inputWidth;
    const T* weight = weight_data + c * filterHeight * filterWidth;
    T value = 0;
    for (int kh = 0; kh < filterHeight; ++kh) {
      for (int kw = 0; kw < filterWidth; ++kw) {
        const int h_out_s = h + paddingH - kh;
        const int w_out_s = w + paddingW - kw;
        if (((h_out_s % strideH) == 0) && ((w_out_s % strideW) == 0)) {
          const int h_out = h_out_s / strideH;
          const int w_out = w_out_s / strideW;
	     // TODO(zhaolong) : the 'if' affect the effectiveness, it needs to optimize
          if ((h_out >= 0) && (h_out < outputHeight)
                && (w_out >= 0) && (w_out < outputWidth)) {
            const int offset = ((n * outputChannels + c) * outputHeight + h_out)
                  * outputWidth + w_out;
            value += (*weight) * top_diff[offset];
          }
        }
        ++weight;
      }
    }
    bottom_diff[index] += value;
  }
}

template <class T>
__global__
void ConvolutionDepthwiseFilterBackward(const int num_i, const int nthreads,
    const T* const top_diff, const T* const inputData,
    const int num, const int outputChannels, const int outputHeight,
    const int outputWidth, const int inputHeight, const int inputWidth,
    const int filterHeight, const int filterWidth, const int strideH,
    const int strideW, const int paddingH, const int paddingW,
    T* const buffer_data) {
  int index =
    (blockIdx.x * gridDim.y + blockIdx.y) * blockDim.x + threadIdx.x;
  if (index < nthreads) {
    const int h = (index / outputWidth) % outputHeight;
    const int w = index % outputWidth;
    const int kh = (index / filterWidth / outputHeight / outputWidth)
          % filterHeight;
    const int kw = (index / outputHeight / outputWidth) % filterWidth;
    const int h_in = -paddingH + h * strideH + kh;
    const int w_in = -paddingW + w * strideW + kw;
    if ((h_in >= 0) && (h_in < inputHeight)
          && (w_in >= 0) && (w_in < inputWidth)) {
      const int c = index / filterHeight / filterWidth / outputHeight / outputWidth;
      const int n = num_i;
      const int top_offset = ((n * outputChannels + c) * outputHeight + h)
            * outputWidth + w;
      const int bottom_offset = ((n * outputChannels + c) * inputHeight + h_in)
            * inputWidth + w_in;
      buffer_data[index] = top_diff[top_offset] * inputData[bottom_offset];
    } else {
      buffer_data[index] = 0;
    }
  }
}

template <class T>
class DepthwiseConvFunctor<DEVICE_TYPE_GPU, T>{
public:
  void operator()(int outputSize, 
            const T* inputData, 
            const T* filterData,
            int batchSize,
            int outputChannels,
            int outputHeight,
            int outputWidth,
			int inputHeight,
			int inputWidth,
            int filterHeight,
            int filterWidth,
            int strideH,
            int strideW,
            int paddingH,
            int paddingW,
            T* outputData){

    size_t blocks = (outputSize + 1024 -1) / 1024;
    size_t blockX = 512;
    size_t blockY = (blocks+512-1)/512;
    dim3 threads(1024, 1);
    dim3 grid(blockX, blockY);
    
    ConvolutionDepthwiseForward<T>
        <<< grid, threads, 0, STREAM_DEFAULT >>>(
            outputSize, 
            inputData, 
            filterData,
            batchSize,
            outputChannels,
            outputHeight,
            outputWidth,
			inputHeight,
			inputWidth,
            filterHeight,
            filterWidth,
            strideH,
            strideW,
            paddingH,
            paddingW,
            outputData);
    }
};

template <class T>
class DepthwiseConvGradInputFunctor<DEVICE_TYPE_GPU, T>{
public:
  void operator()(int inputSize,
            const T* outputGrad,
            const T* filterData,
            int batchSize,
            int outputChannels,
            int outputHeight,
            int outputWidth,
            int inputHeight,
            int inputWidth,
            int filterHeight,
            int filterWidth,
            int strideH,
            int strideW,
            int paddingH,
            int paddingW,
                T* inputGrad){

    size_t blocks = (inputSize + 1024 -1) / 1024;
    size_t blockX = 512;
    size_t blockY = (blocks+512-1)/512;
    dim3 threads(1024, 1);
    dim3 grid(blockX, blockY);

    ConvolutionDepthwiseInputBackward<T>
          // NOLINT_NEXT_LINE(whitespace/operators)
        <<< grid, threads, 0, STREAM_DEFAULT >>>(
            inputSize,
            outputGrad,
            filterData,
            batchSize,
            outputChannels,
            outputHeight,
            outputWidth,
            inputHeight,
            inputWidth,
            filterHeight,
            filterWidth,
            strideH,
            strideW,
            paddingH,
            paddingW,
            inputGrad);
    }
};

template <class T>
class DepthwiseConvGradFilterFunctor<DEVICE_TYPE_GPU, T> {
public:
  void operator()(int num_i,
                int colDataSize,
                const T* outputGrad,
                const T* inputData,
                int batchSize,
                int outputChannels,
                int outputHeight,
                int outputWidth,
                int inputHeight,
                int inputWidth,
                int filterHeight,
                int filterWidth,
                int strideH,
                int strideW,
                int paddingH,
                int paddingW,
                T* colData,
                T* multiplierData,
                T* filterGrad){

        size_t blocks = (colDataSize + 1024 -1) / 1024;
        size_t blockX = 512;
        size_t blockY = (blocks+512-1)/512;
        dim3 threads(1024, 1);
        dim3 grid(blockX, blockY);

	    ConvolutionDepthwiseFilterBackward<T>
            <<< grid, threads, 0, STREAM_DEFAULT >>>(
                num_i,
                colDataSize,
                outputGrad,
                inputData,
                batchSize,
                outputChannels,
                outputHeight,
                outputWidth,
                inputHeight,
                inputWidth,
                filterHeight,
                filterWidth,
                strideH,
                strideW,
                paddingH,
                paddingW,
                colData
            );
        GemmFunctor<DEVICE_TYPE_GPU, real> gemm;
        int M = colDataSize / outputHeight / outputWidth;
        int N = 1;
        int K = outputHeight * outputWidth;
        gemm(CblasNoTrans,
            CblasNoTrans,
            M,
            N,
            K,
            (T)1.0,
            colData,
            K,
            multiplierData,
            N,
            (T)1.0,
            filterGrad,
            N);
        //gemv
    }
};

#ifdef PADDLE_TYPE_DOUBLE
using real=double;
#else 
using real=float;
#endif
template class DepthwiseConvGradInputFunctor<DEVICE_TYPE_GPU, real>;
template class DepthwiseConvFunctor<DEVICE_TYPE_GPU, real>;
template class DepthwiseConvGradFilterFunctor<DEVICE_TYPE_GPU, real>;

}  // namespace paddle