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Sprout/sprout/math/atanh.hpp
2013-08-07 00:15:09 +09:00

57 lines
1.7 KiB
C++

#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 {
template<typename T>
inline SPROUT_CONSTEXPR T
atanh_impl(T x) {
return sprout::math::log((1 + x) / (1 - x)) / 2;
}
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
: std::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::detail::atanh(static_cast<double>(x));
}
} // namespace detail
using sprout::math::detail::atanh;
} // namespace math
using sprout::math::atanh;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_ATANH_HPP