LORENE
zero_premier.C
1
/*
2
* Locates the first zero of a function in a given interval.
3
*
4
*/
5
6
/*
7
* Copyright (c) 1999-2001 Eric Gourgoulhon
8
*
9
* This file is part of LORENE.
10
*
11
* LORENE is free software; you can redistribute it and/or modify
12
* it under the terms of the GNU General Public License as published by
13
* the Free Software Foundation; either version 2 of the License, or
14
* (at your option) any later version.
15
*
16
* LORENE is distributed in the hope that it will be useful,
17
* but WITHOUT ANY WARRANTY; without even the implied warranty of
18
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19
* GNU General Public License for more details.
20
*
21
* You should have received a copy of the GNU General Public License
22
* along with LORENE; if not, write to the Free Software
23
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24
*
25
*/
26
27
28
char
zero_premier_C[] =
"$Header: /cvsroot/Lorene/C++/Source/Non_class_members/Utilities/zero_premier.C,v 1.3 2014/10/13 08:53:32 j_novak Exp $"
;
29
30
/*
31
* $Id: zero_premier.C,v 1.3 2014/10/13 08:53:32 j_novak Exp $
32
* $Log: zero_premier.C,v $
33
* Revision 1.3 2014/10/13 08:53:32 j_novak
34
* Lorene classes and functions now belong to the namespace Lorene.
35
*
36
* Revision 1.2 2002/10/16 14:37:12 j_novak
37
* Reorganization of #include instructions of standard C++, in order to
38
* use experimental version 3 of gcc.
39
*
40
* Revision 1.1.1.1 2001/11/20 15:19:29 e_gourgoulhon
41
* LORENE
42
*
43
* Revision 1.2 2000/01/04 10:57:51 eric
44
* Le test f1*f2 < 0. est remplace par f1*f2 <= double(0).
45
*
46
* Revision 1.1 1999/12/24 13:00:10 eric
47
* Initial revision
48
*
49
*
50
* $Header: /cvsroot/Lorene/C++/Source/Non_class_members/Utilities/zero_premier.C,v 1.3 2014/10/13 08:53:32 j_novak Exp $
51
*
52
*/
53
54
// Headers Lorene
55
#include "headcpp.h"
56
#include "param.h"
57
//****************************************************************************
58
59
namespace
Lorene
{
60
61
bool
zero_premier
(
double
(*f)(
double
,
const
Param
&),
const
Param
& par,
62
double
a,
double
b,
int
n,
double
& a0,
double
& b0) {
63
64
double
dx = (b-a)/
double
(n) ;
65
66
a0 = a ;
67
b0 = a0 + dx ;
68
69
double
f1 = f(a0, par) ;
70
bool
trouve = false ;
71
72
for
(
int
i=0; i<n; i++) {
73
double
f2 = f(b0, par) ;
74
if
(f1*f2 <=
double
(0)) {
// on a encadre le zero
75
trouve = true ;
76
break ;
77
}
78
79
// On passe au sous-intervalle suivant :
80
a0 = b0 ;
81
f1 = f2 ;
82
b0 += dx ;
83
}
84
85
return
trouve ;
86
87
}
88
}
Lorene
Lorene prototypes.
Definition:
app_hor.h:64
Lorene::Param
Parameter storage.
Definition:
param.h:125
Lorene::zero_premier
bool zero_premier(double(*f)(double, const Param &), const Param &par, double a, double b, int n, double &a0, double &b0)
Locates the sub-interval containing the first zero of a function in a given interval.
Definition:
zero_premier.C:61
C++
Source
Non_class_members
Utilities
zero_premier.C
Generated by
1.8.12