77 lines
1.8 KiB
C++
77 lines
1.8 KiB
C++
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// (C) Copyright John Maddock 2006.
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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_SPECIAL_HERMITE_HPP
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#define BOOST_MATH_SPECIAL_HERMITE_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/math/tools/config.hpp>
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#include <boost/math/policies/error_handling.hpp>
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namespace boost{
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namespace math{
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// Recurrance relation for Hermite polynomials:
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template <class T1, class T2, class T3>
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inline typename tools::promote_args<T1, T2, T3>::type
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hermite_next(unsigned n, T1 x, T2 Hn, T3 Hnm1)
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{
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return (2 * x * Hn - 2 * n * Hnm1);
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}
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namespace detail{
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// Implement Hermite polynomials via recurrance:
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template <class T>
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T hermite_imp(unsigned n, T x)
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{
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T p0 = 1;
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T p1 = 2 * x;
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if(n == 0)
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return p0;
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unsigned c = 1;
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while(c < n)
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{
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std::swap(p0, p1);
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p1 = hermite_next(c, x, p0, p1);
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++c;
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}
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return p1;
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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
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hermite(unsigned n, 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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return policies::checked_narrowing_cast<result_type, Policy>(detail::hermite_imp(n, static_cast<value_type>(x)), "boost::math::hermite<%1%>(unsigned, %1%)");
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}
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template <class T>
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inline typename tools::promote_args<T>::type
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hermite(unsigned n, T x)
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{
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return boost::math::hermite(n, x, policies::policy<>());
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}
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} // namespace math
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} // namespace boost
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#endif // BOOST_MATH_SPECIAL_HERMITE_HPP
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