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/* Test file for mpfr_sub_ui
Copyright 2000-2014 Free Software Foundation, Inc.
Contributed by the AriC and Caramel 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
http://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_print_binary(zz);
printf ("\nmpfr_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_print_binary(y); puts ("");
printf ("u="); mpfr_print_binary(u); puts ("");
printf ("v="); mpfr_print_binary(v); puts ("");
printf ("w="); mpfr_print_binary(w); puts ("");
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_sub_ui (y, x, 1L, MPFR_RNDN);
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 INTEGER_TYPE unsigned long
#define RAND_FUNCTION(x) mpfr_random2(x, MPFR_LIMB_SIZE (x), 1, RANDS)
#include "tgeneric_ui.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_ui (2, 1000, 100);
tests_end_mpfr ();
return 0;
}
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