_log_add_exp_helper Class — pytorch Architecture

Source Code

aten/src/ATen/native/cpu/LogAddExp.h lines 21–33

template <typename scalar_t>
scalar_t _log_add_exp_helper(scalar_t x, scalar_t y) {
  // Reference : https://www.tensorflow.org/api_docs/python/tf/math/cumulative_logsumexp
  scalar_t min = at::_isnan(y) ? y : std::min(x, y); // std::min returns first arg if one of the args is nan
  scalar_t max = at::_isnan(y) ? y : std::max(x, y); // std::max returns first arg if one of the args is nan
  if (min != max || std::isfinite(min)) {
    // nan will be propagated here
    return std::log1p(std::exp(min - max)) + max;
  } else {
    // special case to correctly handle infinite cases
    return x;
  }
}