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
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
/*****************************************************************************
* *
* unuran -- Universal Non-Uniform Random number generator *
* *
*****************************************************************************
* *
* FILE: compute_machine_constants.c *
* *
* Compute some machine constants and print to stdout *
* *
*****************************************************************************
* *
* Copyright (c) 2000-2006 Wolfgang Hoermann and Josef Leydold *
* Department of Statistics and Mathematics, WU Wien, Austria *
* *
* 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., *
* 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA *
* *
*****************************************************************************/
/*---------------------------------------------------------------------------*/
#include <float.h>
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
/*---------------------------------------------------------------------------*/
/** TODO:
#define MAXLGM 2.556348e305
**/
/*---------------------------------------------------------------------------*/
int main(void)
{
printf("/** File automatically created by scripts/compute_machine_constants **/\n\n");
printf("/*****************************************************************************\n");
printf(" * *\n");
printf(" * unuran -- Universal Non-Uniform Random number generator *\n");
printf(" * *\n");
printf(" *****************************************************************************/\n");
printf("\n");
printf("/*---------------------------------------------------------------------------*/\n");
printf("#ifndef UNUR_FP_CONST_SOURCE_H_SEEN\n");
printf("#define UNUR_FP_CONST_SOURCE_H_SEEN\n");
printf("/*---------------------------------------------------------------------------*/\n\n");
/* Epsilon for comparision of two doubles: */
/* Two doubles are considered equal if there relative difference is */
/* less than UNUR_EPSILON (see file `./methods/source_fp.h' for details). */
/* Use 100 times DBL_EPSILON. */
printf("/* maximal relative error when testing equality of two doubles */\n");
printf("#define UNUR_EPSILON %.30g\n\n", 100.*DBL_EPSILON);
/* Square root of machine epsilon. It is used to compare two doubles */
/* when round-off errors have to be considered */
/* (see file `./methods/source_fp.h' for details). */
printf("/* square root of DBL_EPSILON */\n");
printf("#define UNUR_SQRT_DBL_EPSILON %.30g\n\n", sqrt(DBL_EPSILON));
/* Log of machine epsilon. */
/* Negative of least number x such that exp(x)-1. == exp(x) */
printf("/* log of DBL_EPSILON */\n");
printf("#define UNUR_LOG_DBL_EPSILON %.30g\n\n", log(DBL_EPSILON));
/* Constants used by CEPHES functions */
printf("/* the machine roundoff error */\n");
printf("#define MACHEP %.30g\n\n", DBL_EPSILON/2.);
printf("/* largest argument for exp() */\n");
printf("#define MAXLOG %.30g\n\n", log(DBL_MAX));
printf("/* smallest argument for exp() without underflow */\n");
printf("#define MINLOG %.30g\n\n", log(DBL_MIN));
printf("/* the maximal number that pow(x,x-0.5) has no overflow */\n");
printf("/* we use a (very) conservative portable bound */\n");
printf("#define MAXSTIR %.30g\n\n", log(DBL_MAX) / log(log(DBL_MAX)) );
printf("/*---------------------------------------------------------------------------*/\n");
printf("#endif /* UNUR_FP_CONST_SOURCE_H_SEEN */\n");
printf("/*---------------------------------------------------------------------------*/\n");
exit (0);
}
/*---------------------------------------------------------------------------*/
|
