mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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69 lines
2.2 KiB
C++
69 lines
2.2 KiB
C++
#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 <limits>
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#include <type_traits>
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#include <sprout/config.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/factorial.hpp>
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#include <sprout/math/constants.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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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::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 FloatType>
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inline SPROUT_CONSTEXPR FloatType
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cos_impl(FloatType x) {
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typedef typename sprout::math::detail::float_compute<FloatType>::type type;
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return static_cast<FloatType>(
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type(1) + sprout::math::detail::cos_impl_1(
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sprout::detail::pow2(static_cast<type>(x)),
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1, sprout::math::factorial_limit<type>() / 2 + 1
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)
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);
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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 x == 0 ? FloatType(1)
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: x == std::numeric_limits<FloatType>::infinity() || x == -std::numeric_limits<FloatType>::infinity()
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? std::numeric_limits<FloatType>::quiet_NaN()
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: sprout::math::detail::cos_impl(sprout::math::fmod(x, sprout::math::two_pi<FloatType>()))
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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::detail::cos(static_cast<double>(x));
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}
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} // namespace detail
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using NS_SPROUT_MATH_DETAIL::cos;
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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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