stirling_approx_tail Class — pytorch Architecture

Source Code

aten/src/ATen/native/Distributions.h lines 122–141

template<typename scalar_t>
C10_DEVICE scalar_t stirling_approx_tail(scalar_t k) {
  constexpr static scalar_t kTailValues[] = {
    0.0810614667953272,
    0.0413406959554092,
    0.0276779256849983,
    0.02079067210376509,
    0.0166446911898211,
    0.0138761288230707,
    0.0118967099458917,
    0.0104112652619720,
    0.00925546218271273,
    0.00833056343336287
  };
  if (k < std::size(kTailValues)) {
    return kTailValues[static_cast<size_t>(k)];
  }
  scalar_t kp1sq = (k + 1) * (k + 1);
  return (1.0 / 12 - (1.0 / 360 - 1.0 / 1260 / kp1sq) / kp1sq) / (k + 1);
}