grid_sampler_compute_source_index_set_grad Class — pytorch Architecture

Source Code

aten/src/ATen/native/GridSampler.h lines 177–202

template <typename scalar_t>
static inline scalar_t grid_sampler_compute_source_index_set_grad(
    scalar_t coord,
    int64_t size,
    GridSamplerPadding padding_mode,
    bool align_corners,
    scalar_t *grad_in) {
  scalar_t grad_clip, grad_refl;
  coord = grid_sampler_unnormalize_set_grad(coord, size, align_corners, grad_in);
  if (padding_mode == GridSamplerPadding::Border) {
    // clip coordinates to image borders
    coord = clip_coordinates_set_grad(coord, size, &grad_clip);
    *grad_in = (*grad_in) * grad_clip;
  } else if (padding_mode == GridSamplerPadding::Reflection) {
    // reflect coordinates by image borders
    if (align_corners) {
      coord = reflect_coordinates_set_grad(coord, 0, 2*(size - 1), &grad_refl);
    } else {
      coord = reflect_coordinates_set_grad(coord, -1, 2*size - 1, &grad_refl);
    }
    // clip coordinates to image borders
    coord = clip_coordinates_set_grad(coord, size, &grad_clip);
    *grad_in = (*grad_in) * grad_refl * grad_clip;
  }
  return coord;
}