1 /* multiroots/convergence.c
2 *
3 * Copyright (C) 1996, 1997, 1998, 1999, 2000, 2007 Brian Gough
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 3 of the License, or (at
8 * your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 */
19
20 #include <config.h>
21 #include <gsl/gsl_math.h>
22 #include <gsl/gsl_errno.h>
23 #include <gsl/gsl_multiroots.h>
24
25 int
gsl_multiroot_test_delta(const gsl_vector * dx,const gsl_vector * x,double epsabs,double epsrel)26 gsl_multiroot_test_delta (const gsl_vector * dx, const gsl_vector * x,
27 double epsabs, double epsrel)
28 {
29 size_t i;
30 int ok = 1;
31 const size_t n = x->size ;
32
33 if (epsrel < 0.0)
34 {
35 GSL_ERROR ("relative tolerance is negative", GSL_EBADTOL);
36 }
37
38 for (i = 0 ; i < n ; i++)
39 {
40 double xi = gsl_vector_get(x,i);
41 double dxi = gsl_vector_get(dx,i);
42 double tolerance = epsabs + epsrel * fabs(xi) ;
43
44 if (fabs(dxi) < tolerance || dxi == 0)
45 {
46 ok = 1;
47 }
48 else
49 {
50 ok = 0;
51 break;
52 }
53 }
54
55 if (ok)
56 return GSL_SUCCESS ;
57
58 return GSL_CONTINUE;
59 }
60
61 int
gsl_multiroot_test_residual(const gsl_vector * f,double epsabs)62 gsl_multiroot_test_residual (const gsl_vector * f, double epsabs)
63 {
64 size_t i;
65
66 double residual = 0;
67
68 const size_t n = f->size;
69
70 if (epsabs < 0.0)
71 {
72 GSL_ERROR ("absolute tolerance is negative", GSL_EBADTOL);
73 }
74
75 for (i = 0 ; i < n ; i++)
76 {
77 double fi = gsl_vector_get(f, i);
78
79 residual += fabs(fi);
80 }
81
82
83 if (residual < epsabs)
84 {
85 return GSL_SUCCESS;
86 }
87
88 return GSL_CONTINUE ;
89 }
90
91