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cosh.hpp
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cosh.hpp
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/*################################################################################
##
## Copyright (C) 2016-2024 Keith O'Hara
##
## This file is part of the GCE-Math C++ library.
##
## Licensed under the Apache License, Version 2.0 (the "License");
## you may not use this file except in compliance with the License.
## You may obtain a copy of the License at
##
## http://www.apache.org/licenses/LICENSE-2.0
##
## Unless required by applicable law or agreed to in writing, software
## distributed under the License is distributed on an "AS IS" BASIS,
## WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
## See the License for the specific language governing permissions and
## limitations under the License.
##
################################################################################*/
/*
* compile-time hyperbolic cosine function
*/
#ifndef _gcem_cosh_HPP
#define _gcem_cosh_HPP
namespace internal
{
template<typename T>
constexpr
T
cosh_compute(const T x)
noexcept
{
return( // NaN check
is_nan(x) ? \
GCLIM<T>::quiet_NaN() :
// indistinguishable from zero
GCLIM<T>::min() > abs(x) ? \
T(1) :
// else
(exp(x) + exp(-x)) / T(2) );
}
}
/**
* Compile-time hyperbolic cosine function
*
* @param x a real-valued input.
* @return the hyperbolic cosine function using \f[ \cosh(x) = \frac{\exp(x) + \exp(-x)}{2} \f]
*/
template<typename T>
constexpr
return_t<T>
cosh(const T x)
noexcept
{
return internal::cosh_compute( static_cast<return_t<T>>(x) );
}
#endif