diff options
Diffstat (limited to 'libstdc++-v3/include/std/complex')
| -rw-r--r-- | libstdc++-v3/include/std/complex | 11 |
1 files changed, 3 insertions, 8 deletions
diff --git a/libstdc++-v3/include/std/complex b/libstdc++-v3/include/std/complex index 3c41b483cd2..d7423433803 100644 --- a/libstdc++-v3/include/std/complex +++ b/libstdc++-v3/include/std/complex @@ -1686,14 +1686,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION std::complex<_Tp> __complex_acosh(const std::complex<_Tp>& __z) { - std::complex<_Tp> __t((__z.real() - __z.imag()) - * (__z.real() + __z.imag()) - _Tp(1.0), - _Tp(2.0) * __z.real() * __z.imag()); - __t = std::sqrt(__t); - if (__z.real() < _Tp()) - __t = -__t; - - return std::log(__t + __z); + // Kahan's formula. + return _Tp(2.0) * std::log(std::sqrt(_Tp(0.5) * (__z + _Tp(1.0))) + + std::sqrt(_Tp(0.5) * (__z - _Tp(1.0)))); } #if _GLIBCXX_USE_C99_COMPLEX_TR1 |