mirror of
https://github.com/bolero-MURAKAMI/Sprout
synced 2024-11-12 21:09:01 +00:00
122 lines
4.3 KiB
C++
122 lines
4.3 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2013 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_MATH_COS_HPP
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#define SPROUT_MATH_COS_HPP
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#include <cstddef>
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#include <type_traits>
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#include <sprout/config.hpp>
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#include <sprout/limits.hpp>
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#include <sprout/detail/pow.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/detail/cosp.hpp>
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//#include <sprout/math/detail/sinp.hpp>
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#include <sprout/math/constants.hpp>
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#include <sprout/math/isnan.hpp>
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#include <sprout/math/fabs.hpp>
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#include <sprout/math/factorial.hpp>
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#include <sprout/math/fmod.hpp>
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#include <sprout/type_traits/enabler_if.hpp>
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namespace sprout {
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namespace math {
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namespace detail {
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#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
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inline SPROUT_CONSTEXPR float
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builtin_cos(float x) {
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return __builtin_cosf(x);
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}
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inline SPROUT_CONSTEXPR double
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builtin_cos(double x) {
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return __builtin_cos(x);
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}
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inline SPROUT_CONSTEXPR long double
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builtin_cos(long double x) {
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return __builtin_cosl(x);
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}
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#endif
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template<typename T>
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inline SPROUT_CONSTEXPR T
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cos_impl_1(T x2, std::size_t n, std::size_t last) {
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return last - n == 1
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? (n % 2 ? -1 : 1) * sprout::detail::pow_n(x2, n) / sprout::math::unchecked_factorial<T>(2 * n)
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: sprout::math::detail::cos_impl_1(x2, n, n + (last - n) / 2)
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+ sprout::math::detail::cos_impl_1(x2, n + (last - n) / 2, last)
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;
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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cos_impl(T x) {
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return T(1) + sprout::math::detail::cos_impl_1(
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sprout::detail::pow2(sprout::math::fmod(x, sprout::math::two_pi<T>())),
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1, sprout::math::factorial_limit<T>() / 2 + 1
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);
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}
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// !!!
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// template<typename T>
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// inline SPROUT_CONSTEXPR T
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// cos_impl_2(T x) {
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// return x <= sprout::math::quarter_pi<T>() ? -sprout::math::detail::cosp(x)
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// : x <= sprout::math::half_pi<T>() ? -sprout::math::detail::sinp(sprout::math::half_pi<T>() - x)
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// : x <= sprout::math::three_quarters_pi<T>() ? sprout::math::detail::sinp(x - sprout::math::half_pi<T>())
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// : sprout::math::detail::cosp(sprout::math::pi<T>() - x)
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// ;
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// }
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// template<typename T>
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// inline SPROUT_CONSTEXPR T
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// cos_impl_1(T x) {
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// return x > sprout::math::pi<T>() ? sprout::math::detail::cos_impl_2(x - sprout::math::pi<T>())
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// : x <= sprout::math::quarter_pi<T>() ? sprout::math::detail::cosp(x)
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// : x <= sprout::math::half_pi<T>() ? sprout::math::detail::sinp(sprout::math::half_pi<T>() - x)
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// : x <= sprout::math::three_quarters_pi<T>() ? -sprout::math::detail::sinp(x - sprout::math::half_pi<T>())
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// : -sprout::math::detail::cosp(sprout::math::pi<T>() - x)
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// ;
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// }
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// template<typename T>
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// inline SPROUT_CONSTEXPR T
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// cos_impl(T x) {
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// return sprout::math::detail::cos_impl_1(sprout::math::fmod(sprout::math::fabs(x), sprout::math::two_pi<T>()));
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// }
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} // namespace detail
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//
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// cos
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//
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template<
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typename FloatType,
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typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR FloatType
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cos(FloatType x) {
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return sprout::math::isnan(x) ? x
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: x == sprout::numeric_limits<FloatType>::infinity() || x == -sprout::numeric_limits<FloatType>::infinity()
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? -sprout::numeric_limits<FloatType>::quiet_NaN()
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#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
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: sprout::math::detail::builtin_cos(x)
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#else
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: x == 0 ? FloatType(1)
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: static_cast<FloatType>(sprout::math::detail::cos_impl(static_cast<typename sprout::math::detail::float_compute<FloatType>::type>(x)))
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#endif
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;
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}
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template<
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typename IntType,
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typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR double
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cos(IntType x) {
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return sprout::math::cos(static_cast<double>(x));
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}
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} // namespace math
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using sprout::math::cos;
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} // namespace sprout
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#endif // #ifndef SPROUT_MATH_COS_HPP
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