Added boost header

test/external/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
+