/usr/include/rheolef/damped-newton-generic.h is in librheolef-dev 6.7-6.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 | # ifndef _RHEO_DAMPED_NEWTON_GENERIC_H
# define _RHEO_DAMPED_NEWTON_GENERIC_H
///
/// This file is part of Rheolef.
///
/// Copyright (C) 2000-2009 Pierre Saramito <Pierre.Saramito@imag.fr>
///
/// Rheolef is free software; you can redistribute it and/or modify
/// it under the terms of the GNU General Public License as published by
/// the Free Software Foundation; either version 2 of the License, or
/// (at your option) any later version.
///
/// Rheolef is distributed in the hope that it will be useful,
/// but WITHOUT ANY WARRANTY; without even the implied warranty of
/// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
/// GNU General Public License for more details.
///
/// You should have received a copy of the GNU General Public License
/// along with Rheolef; if not, write to the Free Software
/// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
///
/// =========================================================================
#include "rheolef/dis_time.h"
#include "rheolef/newton-backtrack.h"
namespace rheolef {
template <class Problem, class Preconditioner, class Field, class Real, class Size>
int damped_newton (Problem P, Preconditioner T, Field& u, Real& tol, Size& max_iter, odiststream *p_derr = 0) {
const Real delta_u_max_factor = 100;
Real norm_delta_u_max = delta_u_max_factor*std::max(P.space_norm(u), Real(1.));
Real lambda = 1;
Real Tu = 0;
double t0 = dis_time();
if (p_derr) *p_derr << "# damped-Newton: n r T lambda cpu" << std::endl << std::flush;
for (Size n = 0; true; n++) {
P.update_derivative (u);
Field Fu = P.residue(u);
Field delta_u = -P.derivative_solve (Fu);
Tu = T(P,Fu,delta_u);
if (p_derr) *p_derr << n << " " << P.dual_space_norm(Fu) << " " << sqrt(2.*Tu)
<< " " << lambda << " " << dis_time()-t0 << std::endl << std::flush;
if (2.*Tu <= sqr(tol) || n >= max_iter) {
max_iter = n;
tol = sqrt(2.*Tu);
return 0;
}
Real slope = T.slope(P, Fu, delta_u);
Field u_old = u;
Real Tu_old = Tu;
lambda = 1;
int status = newton_backtrack (
P, T, u_old, Tu_old, delta_u, slope, norm_delta_u_max, u, Fu, Tu, lambda, p_derr);
if (status != 0) {
// check if grad(T)(u) approx 0 ?
// let T(u) = 0.5*|A*F(u)|_M
// compute grad(T) = F(u)^T A^T M A F(u)
// and compare to F(u) : |grad(T)(u)| / |F(u)| > tol ?
Field Gu = T.grad(P,Fu);
const Float eps_mach = std::numeric_limits<Float>::epsilon();
max_iter = n;
tol = sqrt(2.*Tu);
if (P.space_norm(Gu) > eps_mach*P.dual_space_norm(Fu)) {
if (p_derr) *p_derr << "# damped-Newton: warning: machine precision reached" << std::endl << std::flush;
return 0;
} else {
if (p_derr) *p_derr << "# damped-Newton: warning: gradient is zero up to machine precision" << std::endl << std::flush;
return 1;
}
}
}
tol = sqrt(2*Tu);
return 1;
}
}// namespace rheolef
# endif // _RHEO_DAMPED_NEWTON_GENERIC_H
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