Sprout/sprout/math/log1p.hpp
2013-04-23 19:03:03 +09:00

44 lines
1.2 KiB
C++

#ifndef SPROUT_MATH_LOG1P_HPP
#define SPROUT_MATH_LOG1P_HPP
#include <limits>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/math/detail/config.hpp>
#include <sprout/math/log.hpp>
#include <sprout/type_traits/enabler_if.hpp>
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
log1p(FloatType x) {
return x == 0 ? FloatType(0)
: x == -1 ? -std::numeric_limits<FloatType>::infinity()
: x == std::numeric_limits<FloatType>::infinity() ? std::numeric_limits<FloatType>::infinity()
: x < -1 ? std::numeric_limits<FloatType>::quiet_NaN()
: sprout::log(1 + x)
;
}
template<
typename IntType,
typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR double
log1p(IntType x) {
return sprout::math::detail::log1p(static_cast<double>(x));
}
} // namespace detail
using NS_SPROUT_MATH_DETAIL::log1p;
} // namespace math
using sprout::math::log1p;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_LOG1P_HPP