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https://github.com/bolero-MURAKAMI/Sprout.git
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78 lines
2.4 KiB
C++
78 lines
2.4 KiB
C++
#ifndef SPROUT_MATH_COSH_HPP
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#define SPROUT_MATH_COSH_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/type_traits/enabler_if.hpp>
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#include <sprout/type_traits/float_promote.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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cosh_impl_1(T x2, std::size_t n, std::size_t last) {
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return last - n == 1
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? sprout::detail::pow_n(x2, n) / sprout::math::unchecked_factorial<T>(2 * n)
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: sprout::math::detail::cosh_impl_1(x2, n, n + (last - n) / 2)
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+ sprout::math::detail::cosh_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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cosh_impl(T x) {
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return T(1) + sprout::math::detail::cosh_impl_1(
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x * x,
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1, sprout::math::factorial_limit<T>() / 2 + 1
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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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cosh(FloatType x) {
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return x == std::numeric_limits<FloatType>::infinity()
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|| x == -std::numeric_limits<FloatType>::infinity()
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? std::numeric_limits<FloatType>::infinity()
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#if SPROUT_USE_BUILTIN_CMATH_FUNCTION
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: std::cosh(x)
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#else
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: x == 0 ? FloatType(1)
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: static_cast<FloatType>(sprout::math::detail::cosh_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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cosh(IntType x) {
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return sprout::math::detail::cosh(static_cast<double>(x));
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}
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} // namespace detail
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//
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// cosh
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//
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template<
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typename ArithmeticType,
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typename sprout::enabler_if<std::is_arithmetic<ArithmeticType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR typename sprout::float_promote<ArithmeticType>::type
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cosh(ArithmeticType x) {
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return sprout::math::detail::cosh(x);
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}
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} // namespace math
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using sprout::math::cosh;
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} // namespace sprout
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#endif // #ifndef SPROUT_MATH_COSH_HPP
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