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- // 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_SIN_PI_HPP
- #define BOOST_MATH_SIN_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/math_fwd.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>
- inline T sin_pi_imp(T x, const Policy& pol)
- {
- BOOST_MATH_STD_USING // ADL of std names
- if(x < 0)
- return -sin_pi_imp(T(-x), pol);
- // sin of pi*x:
- bool invert;
- if(x < 0.5)
- return sin(constants::pi<T>() * x);
- if(x < 1)
- {
- invert = true;
- x = -x;
- }
- else
- invert = false;
- T rem = floor(x);
- if(iconvert(rem, pol) & 1)
- invert = !invert;
- rem = x - rem;
- if(rem > 0.5f)
- rem = 1 - rem;
- if(rem == 0.5f)
- return static_cast<T>(invert ? -1 : 1);
-
- rem = sin(constants::pi<T>() * rem);
- return invert ? T(-rem) : rem;
- }
- } // namespace detail
- template <class T, class Policy>
- inline typename tools::promote_args<T>::type sin_pi(T x, const Policy&)
- {
- typedef typename tools::promote_args<T>::type result_type;
- typedef typename policies::evaluation<result_type, Policy>::type value_type;
- typedef typename policies::normalise<
- Policy,
- policies::promote_float<false>,
- policies::promote_double<false>,
- policies::discrete_quantile<>,
- policies::assert_undefined<>,
- // We want to ignore overflows since the result is in [-1,1] and the
- // check slows the code down considerably.
- policies::overflow_error<policies::ignore_error> >::type forwarding_policy;
- return policies::checked_narrowing_cast<result_type, forwarding_policy>(boost::math::detail::sin_pi_imp<value_type>(x, forwarding_policy()), "sin_pi");
- }
- template <class T>
- inline typename tools::promote_args<T>::type sin_pi(T x)
- {
- return boost::math::sin_pi(x, policies::policy<>());
- }
- } // namespace math
- } // namespace boost
- #endif
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