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/*
* Function zero_list
* Locates approximatively all the zeros of a function in a given interval
*
* (see file utilitaires.h for documentation)
*
*/
/*
* Copyright (c) 2003 Eric Gourgoulhon
*
* This file is part of LORENE.
*
* LORENE 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.
*
* LORENE 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 LORENE; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
char 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 $" ;
/*
* $Id: zero_list.C,v 1.2 2014/10/13 08:53:32 j_novak Exp $
* $Log: zero_list.C,v $
* Revision 1.2 2014/10/13 08:53:32 j_novak
* Lorene classes and functions now belong to the namespace Lorene.
*
* Revision 1.1 2003/09/08 20:22:02 e_gourgoulhon
* First version
*
*
* $Header: /cvsroot/Lorene/C++/Source/Non_class_members/Utilities/zero_list.C,v 1.2 2014/10/13 08:53:32 j_novak Exp $
*
*/
// Headers Lorene
#include "param.h"
#include "tbl.h"
//****************************************************************************
namespace Lorene {
void zero_list( double (*f)(double, const Param&), const Param& par,
double xmin, double xmax, int nsub,
Tbl*& az, Tbl*& bz ) {
int nzero = 0 ;
double dx = (xmax-xmin) / double(nsub) ;
double f1 = f(xmin, par) ;
double x1 = xmin ;
double x2 = xmin + dx ;
double* borne_inf = new double[nsub] ; // At maximum nsub zeros
double* borne_sup = new double[nsub] ;
for (int i=0; i<nsub; i++) {
double f2 = f(x2, par) ;
if (f1*f2 < 0.) { // A zero has been found
borne_inf[nzero] = x1 ;
borne_sup[nzero] = x2 ;
nzero += 1 ;
}
// Next sub-interval :
x1 = x2 ;
f1 = f2 ;
x2 += dx ;
}
// Result:
az = new Tbl(nzero) ;
bz = new Tbl(nzero) ;
if (nzero > 0) {
az->set_etat_qcq() ;
bz->set_etat_qcq() ;
for (int i=0; i<nzero; i++) {
az->set(i) = borne_inf[i] ;
bz->set(i) = borne_sup[i] ;
}
}
delete [] borne_inf ;
delete [] borne_sup ;
}
}
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