mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
synced 2024-11-14 10:39:05 +00:00
123 lines
4.4 KiB
C++
123 lines
4.4 KiB
C++
/*=============================================================================
|
||
Copyright (c) 2011-2015 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_POW_HPP
|
||
#define SPROUT_MATH_POW_HPP
|
||
|
||
#include <type_traits>
|
||
#include <sprout/config.hpp>
|
||
#include <sprout/limits.hpp>
|
||
#include <sprout/math/detail/config.hpp>
|
||
#include <sprout/math/constants.hpp>
|
||
#include <sprout/math/isnan.hpp>
|
||
#include <sprout/math/copysign.hpp>
|
||
#include <sprout/math/fabs.hpp>
|
||
#include <sprout/math/exp.hpp>
|
||
#include <sprout/math/log.hpp>
|
||
#include <sprout/math/is_integer.hpp>
|
||
#include <sprout/math/is_odd.hpp>
|
||
#include <sprout/type_traits/float_promote.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_pow(float x, float y) {
|
||
return __builtin_powf(x, y);
|
||
}
|
||
inline SPROUT_CONSTEXPR double
|
||
builtin_pow(double x, double y) {
|
||
return __builtin_pow(x, y);
|
||
}
|
||
inline SPROUT_CONSTEXPR long double
|
||
builtin_pow(long double x, long double y) {
|
||
return __builtin_powl(x, y);
|
||
}
|
||
#endif
|
||
|
||
template<typename T>
|
||
inline SPROUT_CONSTEXPR T
|
||
pow_impl(T x, T y) {
|
||
return x < 0
|
||
? is_odd(y) ? -sprout::math::exp(y * sprout::math::log(-x))
|
||
: sprout::math::exp(y * sprout::math::log(-x))
|
||
: sprout::math::exp(y * sprout::math::log(x))
|
||
;
|
||
}
|
||
} // namespace detail
|
||
//
|
||
// pow
|
||
//
|
||
// issue:
|
||
// [ !(SPROUT_USE_BUILTIN_CMATH_FUNCTION || SPROUT_USE_BUILTIN_COPYSIGN_FUNCTION) ]
|
||
// pow(-0, y) returns -<2D>‡ for y an odd integer < 0.
|
||
// # returns +<2B>‡ . ( same as pow(+0, y) )
|
||
//
|
||
template<
|
||
typename FloatType,
|
||
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
|
||
>
|
||
inline SPROUT_CONSTEXPR FloatType
|
||
pow(FloatType x, FloatType y) {
|
||
return x == 1 ? FloatType(1)
|
||
: y == 0 ? FloatType(1)
|
||
: sprout::math::isnan(y) ? y
|
||
: sprout::math::isnan(x) ? x
|
||
: x == 0
|
||
? y < 0
|
||
? sprout::math::is_odd(y) ? sprout::math::copysign(sprout::numeric_limits<FloatType>::infinity(), x)
|
||
: sprout::numeric_limits<FloatType>::infinity()
|
||
: sprout::math::is_odd(y) ? x
|
||
: FloatType(0)
|
||
: x == -1 && (y == sprout::numeric_limits<FloatType>::infinity() || y == -sprout::numeric_limits<FloatType>::infinity()) ? FloatType(1)
|
||
: y == -sprout::numeric_limits<FloatType>::infinity()
|
||
? sprout::math::fabs(x) < 1 ? sprout::numeric_limits<FloatType>::infinity()
|
||
: FloatType(0)
|
||
: y == sprout::numeric_limits<FloatType>::infinity()
|
||
? sprout::math::fabs(x) < 1 ? FloatType(0)
|
||
: sprout::numeric_limits<FloatType>::infinity()
|
||
: x == -sprout::numeric_limits<FloatType>::infinity()
|
||
? y < 0
|
||
? sprout::math::is_odd(y) ? -FloatType(0)
|
||
: FloatType(0)
|
||
: sprout::math::is_odd(y) ? -sprout::numeric_limits<FloatType>::infinity()
|
||
: sprout::numeric_limits<FloatType>::infinity()
|
||
: x == sprout::numeric_limits<FloatType>::infinity()
|
||
? y < 0 ? FloatType(0)
|
||
: sprout::numeric_limits<FloatType>::infinity()
|
||
: x < 0 && !sprout::math::is_integer(y) ? sprout::numeric_limits<FloatType>::quiet_NaN()
|
||
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
|
||
: sprout::math::detail::builtin_pow(x, y)
|
||
#else
|
||
: static_cast<FloatType>(sprout::math::detail::pow_impl(
|
||
static_cast<typename sprout::math::detail::float_compute<FloatType>::type>(x),
|
||
static_cast<typename sprout::math::detail::float_compute<FloatType>::type>(y)
|
||
))
|
||
#endif
|
||
;
|
||
}
|
||
|
||
template<
|
||
typename ArithmeticType1,
|
||
typename ArithmeticType2,
|
||
typename sprout::enabler_if<
|
||
std::is_arithmetic<ArithmeticType1>::value && std::is_arithmetic<ArithmeticType2>::value
|
||
>::type = sprout::enabler
|
||
>
|
||
inline SPROUT_CONSTEXPR typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type
|
||
pow(ArithmeticType1 x, ArithmeticType2 y) {
|
||
typedef typename sprout::float_promote<ArithmeticType1, ArithmeticType2>::type type;
|
||
return sprout::math::pow(static_cast<type>(x), static_cast<type>(y));
|
||
}
|
||
} // namespace math
|
||
|
||
using sprout::math::pow;
|
||
} // namespace sprout
|
||
|
||
#endif // #ifndef SPROUT_MATH_POW_HPP
|