re PR libstdc++/51133 (Incorrect implementation of std::tr1::hermite())

2011-11-15  Jason Dick  <dickphd@gmail.com>

	PR libstdc++/51133
	* include/tr1/poly_hermite.tcc (__poly_hermite_recursion): Fix
	wrong sign in recursion relation.

From-SVN: r181381

libstdc++-v3/ChangeLog

+2011-11-15  Jason Dick  <dickphd@gmail.com>
+
+	PR libstdc++/51133
+	* include/tr1/poly_hermite.tcc (__poly_hermite_recursion): Fix
+	wrong sign in recursion relation.
+
 2011-11-14  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* include/c_global/cmath (frexp, modf, remquo): Do not mark constexpr,

libstdc++-v3/include/tr1/poly_hermite.tcc

 // Special functions -*- C++ -*-
 
-// Copyright (C) 2006, 2007, 2008, 2009, 2010
+// Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011
 // Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
@@ -84,7 +84,7 @@ namespace tr1
       unsigned int __i;
       for  (__H_nm2 = __H_0, __H_nm1 = __H_1, __i = 2; __i <= __n; ++__i)
         {
-          __H_n = 2 * (__x * __H_nm1 + (__i - 1) * __H_nm2);
+          __H_n = 2 * (__x * __H_nm1 - (__i - 1) * __H_nm2);
           __H_nm2 = __H_nm1;
           __H_nm1 = __H_n;
         }