Sprout/sprout/math/atanh.hpp
2014-01-08 16:48:12 +09:00

79 lines
2.4 KiB
C++

/*=============================================================================
Copyright (c) 2011-2014 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_MATH_ATANH_HPP
#define SPROUT_MATH_ATANH_HPP
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/limits.hpp>
#include <sprout/math/detail/config.hpp>
#include <sprout/math/detail/float_compute.hpp>
#include <sprout/math/isnan.hpp>
#include <sprout/math/log.hpp>
#include <sprout/math/fabs.hpp>
#include <sprout/type_traits/enabler_if.hpp>
namespace sprout {
namespace math {
namespace detail {
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
inline SPROUT_CONSTEXPR float
builtin_atanh(float x) {
return __builtin_atanhf(x);
}
inline SPROUT_CONSTEXPR double
builtin_atanh(double x) {
return __builtin_atanh(x);
}
inline SPROUT_CONSTEXPR long double
builtin_atanh(long double x) {
return __builtin_atanhl(x);
}
#endif
template<typename T>
inline SPROUT_CONSTEXPR T
atanh_impl(T x) {
return sprout::math::log((1 + x) / (1 - x)) / 2;
}
} // namespace detail
//
// atanh
//
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR FloatType
atanh(FloatType x) {
return sprout::math::isnan(x) ? x
: x == 1 ? sprout::numeric_limits<FloatType>::infinity()
: x == -1 ? -sprout::numeric_limits<FloatType>::infinity()
: sprout::math::fabs(x) > 1 ? -sprout::numeric_limits<FloatType>::quiet_NaN()
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
: sprout::math::detail::builtin_atanh(x)
#else
: x == 0 ? x
: static_cast<FloatType>(sprout::math::detail::atanh_impl(static_cast<typename sprout::math::detail::float_compute<FloatType>::type>(x)))
#endif
;
}
template<
typename IntType,
typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR double
atanh(IntType x) {
return sprout::math::atanh(static_cast<double>(x));
}
} // namespace math
using sprout::math::atanh;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_ATANH_HPP