summaryrefslogtreecommitdiff
path: root/gsl-1.9/sys/infnan.c
blob: fc38404fe22c8e50688c001a290222bf9a51b696 (plain)
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
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
/* sys/infnan.c
 * 
 * Copyright (C) 2001, 2004 Brian Gough
 * 
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#include <config.h>
#include <math.h>

#if HAVE_IEEEFP_H
#include <ieeefp.h>
#endif

double gsl_nan (void);
double gsl_posinf (void);
double gsl_neginf (void);
double gsl_fdiv (const double x, const double y);

double gsl_nan (void)
{
  return gsl_fdiv (0.0, 0.0);
}

double gsl_posinf (void)
{
  return gsl_fdiv (+1.0, 0.0);
}

double gsl_neginf (void)
{
  return gsl_fdiv (-1.0, 0.0);
}


int gsl_isnan (const double x);
int gsl_isinf (const double x);
int gsl_finite (const double x);

#if defined(_MSC_VER) /* Microsoft Visual C++ */
#include <float.h>
int
gsl_isnan (const double x)
{
  return _isnan(x);
}

int
gsl_isinf (const double x)
{
  int fpc = _fpclass(x);

  if (fpc == _FPCLASS_PINF)
    return +1;
  else if (fpc == _FPCLASS_NINF)
    return -1;
  else 
    return 0;
}

int
gsl_finite (const double x)
{
  return _finite(x);
}
#elif HAVE_IEEE_COMPARISONS
int
gsl_isnan (const double x)
{
  int status = (x != x);
  return status;
}

int
gsl_isinf (const double x)
{
  double y = x - x;
  int s = (y != y);

  if (s && x > 0)
    return +1;
  else if (s && x < 0)
    return -1;
  else
    return 0;
}

int
gsl_finite (const double x)
{
  const double y = x - x;
  int status = (y == y);
  return status;
}
#else

#if HAVE_DECL_ISNAN
int
gsl_isnan (const double x)
{
  return isnan(x);
}
#endif

#if HAVE_DECL_ISINF
int
gsl_isinf (const double x)
{
    return isinf(x);
}
#else
int
gsl_isinf (const double x)
{
    return (! gsl_finite(x)) && (! gsl_isnan(x));
}
#endif


#if HAVE_DECL_FINITE
int
gsl_finite (const double x)
{
  return finite(x);
}
#elif HAVE_DECL_ISFINITE
int
gsl_finite (const double x)
{
  return isfinite(x);
}
#endif

#endif