Imported Upstream version 1.49.0upstream/1.49.0

1 files changed, 139 insertions, 0 deletions

diff --git a/boost/math/special_functions/laguerre.hpp b/boost/math/special_functions/laguerre.hpp
new file mode 100644
index 0000000000..070927f26b
--- /dev/null
+++ b/boost/math/special_functions/laguerre.hpp
@@ -0,0 +1,139 @@
+
+//  (C) Copyright John Maddock 2006.
+//  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_SPECIAL_LAGUERRE_HPP
+#define BOOST_MATH_SPECIAL_LAGUERRE_HPP
+
+#ifdef _MSC_VER
+#pragma once
+#endif
+
+#include <boost/math/special_functions/math_fwd.hpp>
+#include <boost/math/tools/config.hpp>
+#include <boost/math/policies/error_handling.hpp>
+
+namespace boost{
+namespace math{
+
+// Recurrance relation for Laguerre polynomials:
+template <class T1, class T2, class T3>
+inline typename tools::promote_args<T1, T2, T3>::type  
+   laguerre_next(unsigned n, T1 x, T2 Ln, T3 Lnm1)
+{
+   typedef typename tools::promote_args<T1, T2, T3>::type result_type;
+   return ((2 * n + 1 - result_type(x)) * result_type(Ln) - n * result_type(Lnm1)) / (n + 1);
+}
+
+namespace detail{
+
+// Implement Laguerre polynomials via recurrance:
+template <class T>
+T laguerre_imp(unsigned n, T x)
+{
+   T p0 = 1;
+   T p1 = 1 - x;
+
+   if(n == 0)
+      return p0;
+
+   unsigned c = 1;
+
+   while(c < n)
+   {
+      std::swap(p0, p1);
+      p1 = laguerre_next(c, x, p0, p1);
+      ++c;
+   }
+   return p1;
+}
+
+template <class T, class Policy>
+inline typename tools::promote_args<T>::type 
+laguerre(unsigned n, T x, const Policy&, const mpl::true_&)
+{
+   typedef typename tools::promote_args<T>::type result_type;
+   typedef typename policies::evaluation<result_type, Policy>::type value_type;
+   return policies::checked_narrowing_cast<result_type, Policy>(detail::laguerre_imp(n, static_cast<value_type>(x)), "boost::math::laguerre<%1%>(unsigned, %1%)");
+}
+
+template <class T>
+inline typename tools::promote_args<T>::type 
+   laguerre(unsigned n, unsigned m, T x, const mpl::false_&)
+{
+   return boost::math::laguerre(n, m, x, policies::policy<>());
+}
+
+} // namespace detail
+
+template <class T>
+inline typename tools::promote_args<T>::type 
+   laguerre(unsigned n, T x)
+{
+   return laguerre(n, x, policies::policy<>());
+}
+
+// Recurrence for associated polynomials:
+template <class T1, class T2, class T3>
+inline typename tools::promote_args<T1, T2, T3>::type  
+   laguerre_next(unsigned n, unsigned l, T1 x, T2 Pl, T3 Plm1)
+{
+   typedef typename tools::promote_args<T1, T2, T3>::type result_type;
+   return ((2 * n + l + 1 - result_type(x)) * result_type(Pl) - (n + l) * result_type(Plm1)) / (n+1);
+}
+
+namespace detail{
+// Laguerre Associated Polynomial:
+template <class T, class Policy>
+T laguerre_imp(unsigned n, unsigned m, T x, const Policy& pol)
+{
+   // Special cases:
+   if(m == 0)
+      return boost::math::laguerre(n, x, pol);
+
+   T p0 = 1;
+   
+   if(n == 0)
+      return p0;
+
+   T p1 = m + 1 - x;
+
+   unsigned c = 1;
+
+   while(c < n)
+   {
+      std::swap(p0, p1);
+      p1 = laguerre_next(c, m, x, p0, p1);
+      ++c;
+   }
+   return p1;
+}
+
+}
+
+template <class T, class Policy>
+inline typename tools::promote_args<T>::type 
+   laguerre(unsigned n, unsigned m, T x, const Policy& pol)
+{
+   typedef typename tools::promote_args<T>::type result_type;
+   typedef typename policies::evaluation<result_type, Policy>::type value_type;
+   return policies::checked_narrowing_cast<result_type, Policy>(detail::laguerre_imp(n, m, static_cast<value_type>(x), pol), "boost::math::laguerre<%1%>(unsigned, unsigned, %1%)");
+}
+
+template <class T1, class T2>
+inline typename laguerre_result<T1, T2>::type 
+   laguerre(unsigned n, T1 m, T2 x)
+{
+   typedef typename policies::is_policy<T2>::type tag_type;
+   return detail::laguerre(n, m, x, tag_type());
+}
+
+} // namespace math
+} // namespace boost
+
+#endif // BOOST_MATH_SPECIAL_LAGUERRE_HPP
+
+
+