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Sprout/sprout/math/sqrt.hpp

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/*=============================================================================
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Copyright (c) 2011-2015 Bolero MURAKAMI
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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)
=============================================================================*/
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#ifndef SPROUT_MATH_SQRT_HPP
#define SPROUT_MATH_SQRT_HPP
#include <type_traits>
#include <sprout/config.hpp>
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#include <sprout/limits.hpp>
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#include <sprout/math/detail/config.hpp>
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#include <sprout/math/detail/float_compute.hpp>
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#include <sprout/math/isnan.hpp>
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#include <sprout/type_traits/enabler_if.hpp>
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namespace sprout {
namespace math {
namespace detail {
#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
inline SPROUT_CONSTEXPR float
builtin_sqrt(float x) {
return __builtin_sqrtf(x);
}
inline SPROUT_CONSTEXPR double
builtin_sqrt(double x) {
return __builtin_sqrt(x);
}
inline SPROUT_CONSTEXPR long double
builtin_sqrt(long double x) {
return __builtin_sqrtl(x);
}
#endif
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template<typename T>
inline SPROUT_CONSTEXPR T
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sqrt_impl_2(T x, T s, T s2) {
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return !(s < s2) ? s2
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: sprout::math::detail::sqrt_impl_2(x, (x / s + s) / 2, s)
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;
}
template<typename T>
inline SPROUT_CONSTEXPR T
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sqrt_impl_1(T x, T s) {
return sprout::math::detail::sqrt_impl_2(x, (x / s + s) / 2, s);
}
template<typename T>
inline SPROUT_CONSTEXPR T
sqrt_impl(T x) {
return sprout::math::detail::sqrt_impl_1(x, x > 1 ? x : T(1));
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}
} // namespace detail
//
// sqrt
//
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR FloatType
sqrt(FloatType x) {
return sprout::math::isnan(x) ? x
: x == sprout::numeric_limits<FloatType>::infinity() ? sprout::numeric_limits<FloatType>::infinity()
: x < 0 ? -sprout::numeric_limits<FloatType>::quiet_NaN()
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#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
: sprout::math::detail::builtin_sqrt(x)
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#else
: x == 0 ? x
: static_cast<FloatType>(sprout::math::detail::sqrt_impl(static_cast<typename sprout::math::detail::float_compute<FloatType>::type>(x)))
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#endif
;
}
template<
typename IntType,
typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR double
sqrt(IntType x) {
return sprout::math::sqrt(static_cast<double>(x));
}
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} // namespace math
using sprout::math::sqrt;
} // namespace sprout
#endif // #ifndef SPROUT_MATH_SQRT_HPP