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
|
/* sys/gsl_compare.c
*
* Copyright (C) 2002 Gert Van den Eynde
*
* This program 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.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Based on fcmp 1.2.2 Copyright (c) 1998-2000 Theodore C. Belding
* University of Michigan Center for the Study of Complex Systems
* Ted.Belding@umich.edu
*
*/
#include "rb_gsl_config.h"
#ifndef GSL_1_3_LATER
#include <config.h>
#include <gsl/gsl_sys.h>
#include <math.h>
int gsl_fcmp(const double x1, const double x2, const double epsilon)
{
int exponent;
double delta, difference;
/* Find exponent of largest absolute value */
{
double max = (fabs (x1) > fabs (x2)) ? x1 : x2;
frexp (max, &exponent);
}
/* Form a neighborhood of size 2 * delta */
delta = ldexp (epsilon, exponent);
difference = x1 - x2;
if (difference > delta) /* x1 > x2 */
{
return 1;
}
else if (difference < -delta) /* x1 < x2 */
{
return -1;
}
else /* -delta <= difference <= delta */
{
return 0; /* x1 ~=~ x2 */
}
}
#endif
|
