// 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(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 | |