Sprout/sprout/complex/acosh.hpp
2016-02-25 18:48:28 +09:00

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/*=============================================================================
Copyright (c) 2011-2016 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
=============================================================================*/
#ifndef SPROUT_COMPLEX_ACOSH_HPP
#define SPROUT_COMPLEX_ACOSH_HPP
#include <sprout/config.hpp>
#include <sprout/limits.hpp>
#include <sprout/math/constants.hpp>
#include <sprout/math/isnan.hpp>
#include <sprout/math/isinf.hpp>
#include <sprout/math/copysign.hpp>
#include <sprout/complex/complex.hpp>
#include <sprout/complex/log.hpp>
#include <sprout/complex/sqrt.hpp>
namespace sprout {
//
// acosh
//
// G.6.2.1 The cacosh functions
// cacosh(conj(z)) = conj(cacosh(z)).
// cacosh(<28>}0 + i0) returns +0 + ip /2.
// cacosh(x + i<>‡) returns +<2B>‡+ ip /2, for finite x.
// cacosh(x + iNaN) returns NaN + iNaN and optionally raises the <20>e<EFBFBD>einvalid<69>f<EFBFBD>f floating-point exception, for finite x.
// cacosh(-<2D>‡+ iy) returns +<2B>‡+ ip , for positive-signed finite y.
// cacosh(+<2B>‡+ iy) returns +<2B>‡+ i0, for positive-signed finite y.
// cacosh(-<2D>‡+ i<>‡) returns +<2B>‡+ i3p /4.
// cacosh(+<2B>‡+ i<>‡) returns +<2B>‡+ ip /4.
// cacosh(<28>}<7D>‡+ iNaN) returns +<2B>‡+ iNaN.
// cacosh(NaN + iy) returns NaN + iNaN and optionally raises the <20>e<EFBFBD>einvalid<69>f<EFBFBD>f floating-point exception, for finite y.
// cacosh(NaN + i<>‡) returns +<2B>‡+ iNaN.
// cacosh(NaN + iNaN) returns NaN + iNaN.
//
template<typename T>
inline SPROUT_CONSTEXPR sprout::complex<T>
acosh(sprout::complex<T> const& x) {
typedef sprout::complex<T> type;
return sprout::math::isnan(x.real())
? sprout::math::isnan(x.imag()) ? x
: sprout::math::isinf(x.imag()) ? type(sprout::numeric_limits<T>::infinity(), x.real())
: type(x.real(), x.real())
: sprout::math::isnan(x.imag())
? sprout::math::isinf(x.real()) ? type(sprout::numeric_limits<T>::infinity(), x.imag())
: type(sprout::numeric_limits<T>::quiet_NaN(), x.imag())
: x.real() == sprout::numeric_limits<T>::infinity()
? sprout::math::isinf(x.imag()) ? type(sprout::numeric_limits<T>::infinity(), sprout::math::copysign(sprout::math::quarter_pi<T>(), x.imag()))
: type(sprout::numeric_limits<T>::infinity(), (x.imag() == 0 ? x.imag() : sprout::math::copysign(T(0), x.imag())))
: x.real() == -sprout::numeric_limits<T>::infinity()
? sprout::math::isinf(x.imag()) ? type(sprout::numeric_limits<T>::infinity(), sprout::math::copysign(sprout::math::three_quarters_pi<T>(), x.imag()))
: type(sprout::numeric_limits<T>::infinity(), sprout::math::copysign(sprout::math::pi<T>(), x.imag()))
: sprout::math::isinf(x.imag()) ? type(sprout::numeric_limits<T>::infinity(), sprout::math::copysign(sprout::math::half_pi<T>(), x.imag()))
: x.real() == 0 && x.imag() == 0 ? type(T(0), sprout::math::copysign(sprout::math::half_pi<T>(), x.imag()))
: T(2) * sprout::log(sprout::sqrt(sprout::math::half<T>() * (x + T(1))) + sprout::sqrt(sprout::math::half<T>() * (x - T(1))))
;
}
} // namespace sprout
#endif // #ifndef SPROUT_COMPLEX_ACOSH_HPP