Rheolef  7.2
an efficient C++ finite element environment
newton.h
Go to the documentation of this file.
1 # ifndef _RHEO_NEWTON_H
2 # define _RHEO_NEWTON_H
3 //
4 // This file is part of Rheolef.
5 //
6 // Copyright (C) 2000-2009 Pierre Saramito <Pierre.Saramito@imag.fr>
7 //
8 // Rheolef is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 2 of the License, or
11 // (at your option) any later version.
12 //
13 // Rheolef is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
17 //
18 // You should have received a copy of the GNU General Public License
19 // along with Rheolef; if not, write to the Free Software
20 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 //
22 // =========================================================================
23 // AUTHOR: Pierre.Saramito@imag.fr
24 // DATE: 14 oct 2009
25 
26 namespace rheolef {
91 } // namespace rheolef
92 
93 namespace rheolef {
94 
96 // [verbatim_newton]
97 template <class Problem, class Field>
98 int newton (const Problem& P, Field& uh, Float& tol, size_t& max_iter, odiststream *p_derr = 0)
99 // [verbatim_newton]
100 {
101  if (p_derr) *p_derr << "# Newton:" << std::endl << "# n r" << std::endl << std::flush;
102  for (size_t n = 0; true; n++) {
103  Field rh = P.residue(uh);
104  Float r = P.dual_space_norm(rh);
105  if (p_derr) *p_derr << n << " " << r << std::endl << std::flush;
106  if (r <= tol) { tol = r; max_iter = n; return 0; }
107  if (n == max_iter) { tol = r; return 1; }
108  P.update_derivative (uh);
109  Field delta_uh = P.derivative_solve (-rh);
110  uh += delta_uh;
111  }
112 }
113 //>newton:
114 }// namespace rheolef
115 # endif // _RHEO_NEWTON_H
see the Float page for the full documentation
odiststream: see the diststream page for the full documentation
Definition: diststream.h:137
This file is part of Rheolef.
int newton(const Problem &P, Field &uh, Float &tol, size_t &max_iter, odiststream *p_derr=0)
see the newton page for the full documentation
Definition: newton.h:98