reflect_coordinates Class — pytorch Architecture

Source Code

aten/src/ATen/native/GridSampler.h lines 87–104

template<typename scalar_t>
static inline scalar_t reflect_coordinates(scalar_t in, int64_t twice_low,
                                           int64_t twice_high) {
  if (twice_low == twice_high) {
    return static_cast<scalar_t>(0);
  }
  scalar_t min = static_cast<scalar_t>(twice_low) / 2;
  scalar_t span = static_cast<scalar_t>(twice_high - twice_low) / 2;
  in = std::fabs(in - min);
  // `fmod` returns same sign as `in`, which is positive after the `fabs` above.
  scalar_t extra = std::fmod(in, span);
  int flips = static_cast<int>(std::floor(in / span));
  if (flips % 2 == 0) {
    return extra + min;
  } else {
    return span - extra + min;
  }
}