diff options
Diffstat (limited to 'boost/math/special_functions/cos_pi.hpp')
-rw-r--r-- | boost/math/special_functions/cos_pi.hpp | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/boost/math/special_functions/cos_pi.hpp b/boost/math/special_functions/cos_pi.hpp new file mode 100644 index 0000000000..93102c1cb3 --- /dev/null +++ b/boost/math/special_functions/cos_pi.hpp @@ -0,0 +1,68 @@ +// Copyright (c) 2007 John Maddock +// Use, modification and distribution are subject to the +// Boost Software License, Version 1.0. (See accompanying file +// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) + +#ifndef BOOST_MATH_COS_PI_HPP +#define BOOST_MATH_COS_PI_HPP + +#ifdef _MSC_VER +#pragma once +#endif + +#include <boost/config/no_tr1/cmath.hpp> +#include <boost/math/tools/config.hpp> +#include <boost/math/special_functions/trunc.hpp> +#include <boost/math/tools/promotion.hpp> +#include <boost/math/constants/constants.hpp> + +namespace boost{ namespace math{ namespace detail{ + +template <class T, class Policy> +T cos_pi_imp(T x, const Policy& pol) +{ + BOOST_MATH_STD_USING // ADL of std names + // cos of pi*x: + bool invert = false; + if(fabs(x) < 0.5) + return cos(constants::pi<T>() * x); + + if(x < 1) + { + x = -x; + } + T rem = floor(x); + if(itrunc(rem, pol) & 1) + invert = !invert; + rem = x - rem; + if(rem > 0.5f) + { + rem = 1 - rem; + invert = !invert; + } + if(rem == 0.5f) + return 0; + + rem = cos(constants::pi<T>() * rem); + return invert ? T(-rem) : rem; +} + +} // namespace detail + +template <class T, class Policy> +inline typename tools::promote_args<T>::type cos_pi(T x, const Policy& pol) +{ + typedef typename tools::promote_args<T>::type result_type; + return boost::math::detail::cos_pi_imp<result_type>(x, pol); +} + +template <class T> +inline typename tools::promote_args<T>::type cos_pi(T x) +{ + return boost::math::cos_pi(x, policies::policy<>()); +} + +} // namespace math +} // namespace boost +#endif + |