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Fix pdiv for complex packets involving infinites.

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libeigen/eigen!2131
This commit is contained in:
Antonio Sánchez
2026-02-15 01:47:32 +00:00
committed by Rasmus Munk Larsen
parent 9b709e8269
commit 1a2b80727c
4 changed files with 89 additions and 69 deletions
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51
Eigen/src/Core/MathFunctions.h
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@@ -2102,6 +2102,57 @@ struct conj_impl<std::complex<T>, true> {
};
#endif
// Complex multiply and division operators.
// Note that these do not handle the case if inf+NaNi, which is considered an infinity.
// This is for consistency with our standard pmul, pdiv implementations.
template <typename T>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE std::complex<T> complex_multiply(const std::complex<T>& a,
const std::complex<T>& b) {
const T a_real = numext::real(a);
const T a_imag = numext::imag(a);
const T b_real = numext::real(b);
const T b_imag = numext::imag(b);
return std::complex<T>(a_real * b_real - a_imag * b_imag, a_imag * b_real + a_real * b_imag);
}
template <typename T>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE std::complex<T> complex_divide_fast(const std::complex<T>& a,
const std::complex<T>& b) {
const T a_real = numext::real(a);
const T a_imag = numext::imag(a);
const T b_real = numext::real(b);
const T b_imag = numext::imag(b);
const T norm = (b_real * b_real + b_imag * b_imag);
return std::complex<T>((a_real * b_real + a_imag * b_imag) / norm, (a_imag * b_real - a_real * b_imag) / norm);
}
template <typename T>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE std::complex<T> complex_divide_smith(const std::complex<T>& a,
const std::complex<T>& b) {
const T a_real = numext::real(a);
const T a_imag = numext::imag(a);
const T b_real = numext::real(b);
const T b_imag = numext::imag(b);
// Smith's complex division (https://arxiv.org/pdf/1210.4539.pdf),
// guards against over/under-flow.
const bool scale_imag = numext::abs(b_imag) <= numext::abs(b_real);
const T rscale = scale_imag ? T(1) : b_real / b_imag;
const T iscale = scale_imag ? b_imag / b_real : T(1);
const T denominator = b_real * rscale + b_imag * iscale;
return std::complex<T>((a_real * rscale + a_imag * iscale) / denominator,
(a_imag * rscale - a_real * iscale) / denominator);
}
template <typename T>
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE std::complex<T> complex_divide(const std::complex<T>& a,
const std::complex<T>& b) {
#if EIGEN_FAST_MATH
return complex_divide_fast(a, b);
#else
return complex_divide_smith(a, b);
#endif
}
} // end namespace internal
} // end namespace Eigen