SpatialUpSamplingBilinear.cu

// Adapted from interp.cpp from Caffe util by Pauline Luc
// Originally developed by George Papandreou
#include "THCUNN.h"
#include "common.h"
#include "THCDeviceTensor.cuh"
#include "THCDeviceTensorUtils.cuh"
#include "THCDeviceUtils.cuh"
#include "THCHalf.h"
#include "THCHalfAutoNumerics.cuh"
#include "THCAtomics.cuh"

template<typename Dtype, typename Acctype>
__global__ void caffe_gpu_interp2_kernel(const int n,
    const Acctype rheight, const Acctype rwidth,
    const THCDeviceTensor<Dtype, 4> data1, THCDeviceTensor<Dtype, 4> data2) {
  int index = threadIdx.x + blockIdx.x * blockDim.x;
  const int batchsize = data1.getSize(0);
  const int channels = data1.getSize(1);
  const int height1 = data1.getSize(2);
  const int width1 = data1.getSize(3);
  const int height2 = data2.getSize(2);
  const int width2 = data2.getSize(3);

  if (index < n) {
    const int w2 = index % width2; // 0:width2-1
    const int h2 = index / width2; // 0:height2-1
    // special case: just copy
    if (height1 == height2 && width1 == width2) {
      const int h1 = h2;
      const int w1 = w2;
      for (int n = 0; n < batchsize ; n++){
        for (int c = 0; c < channels; ++c) {
          const Dtype val = data1[n][c][h1][w1];
          data2[n][c][h2][w2] = val;
        }
      }
      return;
    }
    //
    const Acctype h1r = rheight * h2;
    const int h1 = h1r;
    const int h1p = (h1 < height1 - 1) ? 1 : 0;
    const Acctype h1lambda = h1r - h1;
    const Acctype h0lambda = Acctype(1) - h1lambda;
    //
    const Acctype w1r = rwidth * w2;
    const int w1 = w1r;
    const int w1p = (w1 < width1 - 1) ? 1 : 0;
    const Acctype w1lambda = w1r - w1;
    const Acctype w0lambda = Acctype(1) - w1lambda;
    //
    for (int n = 0; n < batchsize ; n++){
        for (int c = 0; c < channels; ++c) {
        const Acctype val = h0lambda * (w0lambda * data1[n][c][h1][w1]
                            + w1lambda * data1[n][c][h1][w1+w1p])
                            + h1lambda * (w0lambda * data1[n][c][h1+h1p][w1]
                            + w1lambda * data1[n][c][h1+h1p][w1+w1p]);
        data2[n][c][h2][w2] = ScalarConvert<Acctype, Dtype>::to(val);
      }
    }
  }
}

// Backward (adjoint) operation 1 <- 2 (accumulates)
template <typename Dtype, typename Acctype>
__global__ void caffe_gpu_interp2_kernel_backward(const int n,
    const Acctype rheight, const Acctype rwidth,
    THCDeviceTensor<Dtype, 4> data1, const THCDeviceTensor<Dtype, 4> data2){
  int index = threadIdx.x + blockIdx.x * blockDim.x;
  const int batchsize = data1.getSize(0);
  const int channels = data1.getSize(1);
  const int height1 = data1.getSize(2);
  const int width1 = data1.getSize(3);
  const int height2 = data2.getSize(2);
  const int width2 = data2.getSize(3);
  if (index < n) {
    const int w2 = index % width2; // 0:width2-1
    const int h2 = index / width2; // 0:height2-1
    // special case: just copy
    if (height1 == height2 && width1 == width2) {
      const int h1 = h2;
      const int w1 = w2;
      for (int n = 0; n < batchsize ; n++){
        for (int c = 0; c < channels; ++c) {
          const Dtype val = data2[n][c][h1][w1];
          data1[n][c][h2][w2] += val;
        }
      }
      return;
    }
    //
    const Acctype h1r = rheight * h2;
    const int h1 = h1r;
    const int h1p = (h1 < height1 - 1) ? 1 : 0;
    const Acctype h1lambda = h1r - h1;
    const Acctype h0lambda = Acctype(1) - h1lambda;
    //
    const Acctype w1r = rwidth * w2;
    const int w1 = w1r;
    const int w1p = (w1 < width1 - 1) ? 1 : 0;
    const Acctype w1lambda = w1r - w1;
    const Acctype w0lambda = Acctype(1) - w1lambda;
    //
    for (int n = 0; n < batchsize ; n++){
      for (int c = 0; c < channels; ++c) {
        const Dtype d2val = data2[n][c][h2][w2];
        atomicAdd(data1[n][c][h1][w1].data(),
                  ScalarConvert<Acctype, Dtype>::to(h0lambda * w0lambda * d2val));
        atomicAdd(data1[n][c][h1][w1+w1p].data(),
                  ScalarConvert<Acctype, Dtype>::to(h0lambda * w1lambda * d2val));
        atomicAdd(data1[n][c][h1+h1p][w1].data(),
                  ScalarConvert<Acctype, Dtype>::to(h1lambda * w0lambda * d2val));
        atomicAdd(data1[n][c][h1+h1p][w1+w1p].data(),
                  ScalarConvert<Acctype, Dtype>::to(h1lambda * w1lambda * d2val));
      }
    }
  }
}


#include "generic/SpatialUpSamplingBilinear.cu"
#include "THCGenerateFloatTypes.h"