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
|
/* Test file for mpfr_sub_ui
Copyright 2000-2021 Free Software Foundation, Inc.
Contributed by the AriC and Caramba projects, INRIA.
This file is part of the GNU MPFR Library.
The GNU MPFR Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at your
option) any later version.
The GNU MPFR Library 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 Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see
https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
#include <float.h>
#include "mpfr-test.h"
/* checks that x-y gives the right results with 53 bits of precision */
static void
check3 (const char *xs, unsigned long y, mpfr_rnd_t rnd_mode, const char *zs)
{
mpfr_t xx,zz;
mpfr_inits2 (53, xx, zz, (mpfr_ptr) 0);
mpfr_set_str1 (xx, xs);
mpfr_sub_ui (zz, xx, y, rnd_mode);
if (mpfr_cmp_str1(zz, zs))
{
printf ("expected sum is %s, got ", zs);
mpfr_dump (zz);
printf ("mpfr_sub_ui failed for x=%s y=%lu with rnd_mode=%s\n",
xs, y, mpfr_print_rnd_mode (rnd_mode));
exit (1);
}
mpfr_clears (xx, zz, (mpfr_ptr) 0);
}
/* FastTwoSum: if EXP(x) >= EXP(y), u = o(x+y), v = o(u-x), w = o(y-v),
then x + y = u + w
thus if u = o(y-x), v = o(u+x), w = o(v-y), then y-x = u-w */
static void
check_two_sum (mpfr_prec_t p)
{
unsigned int x;
mpfr_t y, u, v, w;
mpfr_rnd_t rnd;
int inexact;
mpfr_inits2 (p, y, u, v, w, (mpfr_ptr) 0);
do
{
x = randlimb ();
}
while (x < 1);
mpfr_urandomb (y, RANDS);
rnd = MPFR_RNDN;
inexact = mpfr_sub_ui (u, y, x, rnd);
mpfr_add_ui (v, u, x, rnd);
mpfr_sub (w, v, y, rnd);
/* as u - (y-x) = w, we should have inexact and w of same sign */
if (((inexact == 0) && mpfr_cmp_ui (w, 0)) ||
((inexact > 0) && (mpfr_cmp_ui (w, 0) <= 0)) ||
((inexact < 0) && (mpfr_cmp_ui (w, 0) >= 0)))
{
printf ("Wrong inexact flag for prec=%u, rnd=%s\n",
(unsigned int) p, mpfr_print_rnd_mode (rnd));
printf ("x=%u\n", x);
printf ("y="); mpfr_dump (y);
printf ("u="); mpfr_dump (u);
printf ("v="); mpfr_dump (v);
printf ("w="); mpfr_dump (w);
printf ("inexact = %d\n", inexact);
exit (1);
}
mpfr_clears (y, u, v, w, (mpfr_ptr) 0);
}
static void
check_nans (void)
{
mpfr_t x, y;
mpfr_init2 (x, 123L);
mpfr_init2 (y, 123L);
/* nan - 1 == nan */
mpfr_set_nan (x);
mpfr_clear_nanflag ();
mpfr_sub_ui (y, x, 1L, MPFR_RNDN);
MPFR_ASSERTN (mpfr_nanflag_p ());
MPFR_ASSERTN (mpfr_nan_p (y));
/* +inf - 1 == +inf */
mpfr_set_inf (x, 1);
mpfr_sub_ui (y, x, 1L, MPFR_RNDN);
MPFR_ASSERTN (mpfr_inf_p (y));
MPFR_ASSERTN (mpfr_sgn (y) > 0);
/* -inf - 1 == -inf */
mpfr_set_inf (x, -1);
mpfr_sub_ui (y, x, 1L, MPFR_RNDN);
MPFR_ASSERTN (mpfr_inf_p (y));
MPFR_ASSERTN (mpfr_sgn (y) < 0);
mpfr_clear (x);
mpfr_clear (y);
}
#define TEST_FUNCTION mpfr_sub_ui
#define ULONG_ARG2
#define RAND_FUNCTION(x) mpfr_random2(x, MPFR_LIMB_SIZE (x), 1, RANDS)
#include "tgeneric.c"
int
main (int argc, char *argv[])
{
mpfr_prec_t p;
int k;
tests_start_mpfr ();
check_nans ();
for (p=2; p<200; p++)
for (k=0; k<200; k++)
check_two_sum (p);
check3 ("0.9999999999", 1, MPFR_RNDN,
"-10000000827403709990903735160827636718750e-50");
test_generic (MPFR_PREC_MIN, 1000, 100);
tests_end_mpfr ();
return 0;
}
|
