mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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130 lines
4.2 KiB
C++
130 lines
4.2 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_ASIN_HPP
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#define SPROUT_MATH_ASIN_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/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/sqrt.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_asin(float x) {
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return __builtin_asinf(x);
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}
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inline SPROUT_CONSTEXPR double
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builtin_asin(double x) {
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return __builtin_asin(x);
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}
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inline SPROUT_CONSTEXPR long double
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builtin_asin(long double x) {
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return __builtin_asinl(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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asin_impl_center_1(T x, T x2) {
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return ((((((((((((
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+ 0.0316658385792867081040808) * x2
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+ -0.0158620440988475212803145) * x2
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+ 0.0192942786775238654913582) * x2
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+ 0.0066153165197009078340075) * x2
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+ 0.0121483892822292648695383) * x2
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+ 0.0138885410156894774969889) * x2
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+ 0.0173593516996479249428647) * x2
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+ 0.0223717830666671020710108) * x2
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+ 0.0303819580081956423799529) * x2
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+ 0.0446428568582815922683933) * x2
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+ 0.0750000000029696112392353) * x2
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+ 0.1666666666666558995379880) * x2
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* x + 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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asin_impl_center(T x) {
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return sprout::math::detail::asin_impl_center_1(x, x * x);
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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asin_impl_tail(T x) {
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return sprout::math::half_pi<T>() + sprout::math::sqrt(T(1) - x)
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* (((((((((((((
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+ -0.0000121189820098929624806) * x
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+ 0.0001307564187657962919394) * x
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+ -0.0006702485124770180942917) * x
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+ 0.0021912255981979442677477) * x
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+ -0.0052049731575223952626203) * x
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+ 0.0097868293573384001221447) * x
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+ -0.0156746038587246716524035) * x
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+ 0.0229883479552557203133368) * x
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+ -0.0331919619444009606270380) * x
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+ 0.0506659694457588602631748) * x
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+ -0.0890259194305537131666744) * x
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+ 0.2145993335526539017488949) * x
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+ -1.5707961988153774692344105)
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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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asin_impl(T x) {
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return x < T(-0.5) ? -sprout::math::detail::asin_impl_tail(-x)
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: x > T(0.5) ? sprout::math::detail::asin_impl_tail(x)
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: sprout::math::detail::asin_impl_center(x)
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;
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}
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} // namespace detail
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//
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// asin
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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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asin(FloatType x) {
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return sprout::math::isnan(x) ? x
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: sprout::math::fabs(x) > 1 ? sprout::numeric_limits<FloatType>::quiet_NaN()
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#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
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: sprout::math::detail::builtin_asin(x)
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#else
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: x == 0 ? x
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: static_cast<FloatType>(
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x < 0 ? -sprout::math::detail::asin_impl(static_cast<typename sprout::math::detail::float_compute<FloatType>::type>(-x))
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: sprout::math::detail::asin_impl(static_cast<typename sprout::math::detail::float_compute<FloatType>::type>(x))
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)
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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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asin(IntType x) {
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return sprout::math::asin(static_cast<double>(x));
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}
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} // namespace math
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using sprout::math::asin;
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} // namespace sprout
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#endif // #ifndef SPROUT_MATH_ASIN_HPP
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