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Fix complex variable notation for division operator to be consistent. (#98057)

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A readability improvement: changes notation in complex division to match comments `(a + bi)/(c + di)` for `constexpr FORCE_INLINE_APPLE complex<T>& operator/=(const complex<U>& rhs)`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/98057
Approved by: https://github.com/ezyang
This commit is contained in:
redwrasse
2023-04-05 12:06:16 +00:00
committed by PyTorch MergeBot
parent 526b564fa0
commit b4420f0fd5
1 changed files with 20 additions and 20 deletions
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40
c10/util/complex.h
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@ -248,36 +248,36 @@ struct alignas(sizeof(T) * 2) complex {
__ubsan_ignore_float_divide_by_zero__ {
// (a + bi) / (c + di) = (ac + bd)/(c^2 + d^2) + (bc - ad)/(c^2 + d^2) i
// the calculation below follows numpy's complex division
T ar = real_;
T ai = imag_;
U br = rhs.real();
U bi = rhs.imag();
T a = real_;
T b = imag_;
U c = rhs.real();
U d = rhs.imag();
#if defined(__GNUC__) && !defined(__clang__)
// std::abs is already constexpr by gcc
auto abs_br = std::abs(br);
auto abs_bi = std::abs(bi);
auto abs_c = std::abs(c);
auto abs_d = std::abs(d);
#else
auto abs_br = br < 0 ? -br : br;
auto abs_bi = bi < 0 ? -bi : bi;
auto abs_c = c < 0 ? -c : c;
auto abs_d = d < 0 ? -d : d;
#endif
if (abs_br >= abs_bi) {
if (abs_br == 0 && abs_bi == 0) {
if (abs_c >= abs_d) {
if (abs_c == 0 && abs_d == 0) {
/* divide by zeros should yield a complex inf or nan */
real_ = ar / abs_br;
imag_ = ai / abs_bi;
real_ = a / abs_c;
imag_ = b / abs_d;
} else {
auto rat = bi / br;
auto scl = 1.0 / (br + bi * rat);
real_ = (ar + ai * rat) * scl;
imag_ = (ai - ar * rat) * scl;
auto rat = d / c;
auto scl = 1.0 / (c + d * rat);
real_ = (a + b * rat) * scl;
imag_ = (b - a * rat) * scl;
}
} else {
auto rat = br / bi;
auto scl = 1.0 / (bi + br * rat);
real_ = (ar * rat + ai) * scl;
imag_ = (ai * rat - ar) * scl;
auto rat = c / d;
auto scl = 1.0 / (d + c * rat);
real_ = (a * rat + b) * scl;
imag_ = (b * rat - a) * scl;
}
return *this;
}