LORENE
zero_list.C
1/*
2 * Function zero_list
3 * Locates approximatively all the zeros of a function in a given interval
4 *
5 * (see file utilitaires.h for documentation)
6 *
7 */
8
9
10/*
11 * Copyright (c) 2003 Eric Gourgoulhon
12 *
13 * This file is part of LORENE.
14 *
15 * LORENE is free software; you can redistribute it and/or modify
16 * it under the terms of the GNU General Public License as published by
17 * the Free Software Foundation; either version 2 of the License, or
18 * (at your option) any later version.
19 *
20 * LORENE is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
23 * GNU General Public License for more details.
24 *
25 * You should have received a copy of the GNU General Public License
26 * along with LORENE; if not, write to the Free Software
27 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
28 *
29 */
30
31char zero_list_C[] = "$Header: /cvsroot/Lorene/C++/Source/Non_class_members/Utilities/zero_list.C,v 1.2 2014/10/13 08:53:32 j_novak Exp $" ;
32
33
34/*
35 * $Id: zero_list.C,v 1.2 2014/10/13 08:53:32 j_novak Exp $
36 * $Log: zero_list.C,v $
37 * Revision 1.2 2014/10/13 08:53:32 j_novak
38 * Lorene classes and functions now belong to the namespace Lorene.
39 *
40 * Revision 1.1 2003/09/08 20:22:02 e_gourgoulhon
41 * First version
42 *
43 *
44 * $Header: /cvsroot/Lorene/C++/Source/Non_class_members/Utilities/zero_list.C,v 1.2 2014/10/13 08:53:32 j_novak Exp $
45 *
46 */
47
48
49// Headers Lorene
50#include "param.h"
51#include "tbl.h"
52
53//****************************************************************************
54
55namespace Lorene {
56
57void zero_list( double (*f)(double, const Param&), const Param& par,
58 double xmin, double xmax, int nsub,
59 Tbl*& az, Tbl*& bz ) {
60
61 int nzero = 0 ;
62
63 double dx = (xmax-xmin) / double(nsub) ;
64 double f1 = f(xmin, par) ;
65 double x1 = xmin ;
66 double x2 = xmin + dx ;
67
68 double* borne_inf = new double[nsub] ; // At maximum nsub zeros
69 double* borne_sup = new double[nsub] ;
70
71 for (int i=0; i<nsub; i++) {
72 double f2 = f(x2, par) ;
73 if (f1*f2 < 0.) { // A zero has been found
74 borne_inf[nzero] = x1 ;
75 borne_sup[nzero] = x2 ;
76 nzero += 1 ;
77 }
78 // Next sub-interval :
79 x1 = x2 ;
80 f1 = f2 ;
81 x2 += dx ;
82 }
83
84 // Result:
85
86 az = new Tbl(nzero) ;
87 bz = new Tbl(nzero) ;
88
89 if (nzero > 0) {
90
91 az->set_etat_qcq() ;
92 bz->set_etat_qcq() ;
93
94 for (int i=0; i<nzero; i++) {
95 az->set(i) = borne_inf[i] ;
96 bz->set(i) = borne_sup[i] ;
97 }
98 }
99
100 delete [] borne_inf ;
101 delete [] borne_sup ;
102
103}
104}
Time evolution with partial storage (*** under development ***).
Definition evolution.h:371
Parameter storage.
Definition param.h:125
Basic array class.
Definition tbl.h:161
void zero_list(double(*f)(double, const Param &), const Param &par, double xmin, double xmax, int nsub, Tbl *&az, Tbl *&bz)
Locates approximatively all the zeros of a function in a given interval.
Definition zero_list.C:57
Lorene prototypes.
Definition app_hor.h:64