Sprout/sprout/math/atanh.hpp
2012-05-05 00:24:10 +09:00

49 lines
1.3 KiB
C++

#ifndef SPROUT_MATH_ATANH_HPP
#define SPROUT_MATH_ATANH_HPP
#include <limits>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/math/log.hpp>
#include <sprout/utility/enabler_if.hpp>
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
# include <cmath>
#endif
namespace sprout {
namespace math {
namespace detail {
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR FloatType
atanh(FloatType x) {
return x < -1 || x > 1 ? std::numeric_limits<FloatType>::quiet_NaN()
: x == -1 ? -std::numeric_limits<FloatType>::infinity()
: x == 1 ? std::numeric_limits<FloatType>::infinity()
: sprout::math::detail::log((1 + x) / (1 - x)) / 2
;
}
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
# if SPROUT_USE_BUILTIN_CMATH_FUNCTION
using std::atanh;
# else
using sprout::math::detail::atanh;
# endif
} // namespace math
using sprout::math::atanh;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_ATANH_HPP