83 lines
2.2 KiB
Plaintext
83 lines
2.2 KiB
Plaintext
// Copyright (c) 2007 John Maddock
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// Use, modification and distribution are subject to the
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// Boost Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_MATH_COS_PI_HPP
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#define BOOST_MATH_COS_PI_HPP
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#ifdef _MSC_VER
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#pragma once
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#endif
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#include <boost/math/special_functions/math_fwd.hpp>
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#include <boost/config/no_tr1/cmath.hpp>
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#include <boost/math/tools/config.hpp>
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#include <boost/math/special_functions/trunc.hpp>
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#include <boost/math/tools/promotion.hpp>
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#include <boost/math/constants/constants.hpp>
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namespace boost{ namespace math{ namespace detail{
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template <class T, class Policy>
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T cos_pi_imp(T x, const Policy& pol)
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{
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BOOST_MATH_STD_USING // ADL of std names
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// cos of pi*x:
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bool invert = false;
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if(fabs(x) < 0.25)
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return cos(constants::pi<T>() * x);
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if(x < 0)
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{
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x = -x;
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}
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T rem = floor(x);
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if(itrunc(rem, pol) & 1)
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invert = !invert;
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rem = x - rem;
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if(rem > 0.5f)
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{
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rem = 1 - rem;
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invert = !invert;
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}
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if(rem == 0.5f)
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return 0;
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if(rem > 0.25f)
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{
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rem = 0.5f - rem;
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rem = sin(constants::pi<T>() * rem);
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}
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else
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rem = cos(constants::pi<T>() * rem);
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return invert ? T(-rem) : rem;
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}
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} // namespace detail
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template <class T, class Policy>
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inline typename tools::promote_args<T>::type cos_pi(T x, const Policy&)
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{
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typedef typename tools::promote_args<T>::type result_type;
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typedef typename policies::evaluation<result_type, Policy>::type value_type;
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typedef typename policies::normalise<
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Policy,
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policies::promote_float<false>,
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policies::promote_double<false>,
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policies::discrete_quantile<>,
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policies::assert_undefined<> >::type forwarding_policy;
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return policies::checked_narrowing_cast<result_type, forwarding_policy>(boost::math::detail::cos_pi_imp<value_type>(x, forwarding_policy()), "cos_pi");
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}
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template <class T>
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inline typename tools::promote_args<T>::type cos_pi(T x)
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{
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return boost::math::cos_pi(x, policies::policy<>());
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}
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} // namespace math
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} // namespace boost
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#endif
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