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/* Test file for mpfr_sub_ui
Copyright 2000, 2001, 2002 Free Software Foundation.
This file is part of the MPFR Library.
The 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 2.1 of the License, or (at your
option) any later version.
The 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 MPFR Library; see the file COPYING. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
MA 02111-1307, USA. */
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "gmp.h"
#include "mpfr.h"
#include "mpfr-impl.h"
#include "mpfr-test.h"
void check_two_sum _PROTO ((mp_prec_t));
void check3 _PROTO ((double, unsigned long, mp_rnd_t, double));
#define check(x,y,r) check3(x,y,r,0.0)
/* checks that x+y gives the same results in double
and with mpfr with 53 bits of precision */
void
check3 (double x, unsigned long y, mp_rnd_t rnd_mode, double z1)
{
double z2;
mpfr_t xx,zz;
mpfr_init(xx);
mpfr_init(zz);
mpfr_set_prec(xx, 53);
mpfr_set_prec(zz, 53);
mpfr_set_d(xx, x, rnd_mode);
mpfr_sub_ui(zz, xx, y, rnd_mode);
#ifdef HAVE_FENV_H
mpfr_set_machine_rnd_mode(rnd_mode);
#endif
if (z1==0.0) z1 = x-y;
z2 = mpfr_get_d(zz);
if (z1!=z2 && !(isnan(z1) && isnan(z2))) {
printf("expected sum is %1.20e, got %1.20e\n",z1,z2);
printf("mpfr_sub_ui failed for x=%1.20e y=%lu with rnd_mode=%s\n",
x, y, mpfr_print_rnd_mode(rnd_mode));
exit(1);
}
mpfr_clear(xx);
mpfr_clear(zz);
}
/* 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 */
void
check_two_sum (mp_prec_t p)
{
unsigned int x;
mpfr_t y, u, v, w;
mp_rnd_t rnd;
int inexact;
mpfr_init2 (y, p);
mpfr_init2 (u, p);
mpfr_init2 (v, p);
mpfr_init2 (w, p);
do
{
x = LONG_RAND ();
}
while (x < 1);
mpfr_random (y);
rnd = LONG_RAND() % 4;
rnd = GMP_RNDN;
inexact = mpfr_sub_ui (u, y, x, GMP_RNDN);
mpfr_add_ui (v, u, x, GMP_RNDN);
mpfr_sub (w, v, y, GMP_RNDN);
/* 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)))
{
fprintf (stderr, "Wrong inexact flag for prec=%u, rnd=%s\n", (unsigned)p,
mpfr_print_rnd_mode (rnd));
printf ("x=%u\n", x);
printf ("y="); mpfr_print_binary(y); putchar('\n');
printf ("u="); mpfr_print_binary(u); putchar('\n');
printf ("v="); mpfr_print_binary(v); putchar('\n');
printf ("w="); mpfr_print_binary(w); putchar('\n');
printf ("inexact = %d\n", inexact);
exit (1);
}
mpfr_clear (y);
mpfr_clear (u);
mpfr_clear (v);
mpfr_clear (w);
}
int
main (int argc, char *argv[])
{
mp_prec_t p;
int k;
#ifdef HAVE_FENV_H
double x; unsigned long y, N; int i,rnd_mode,rnd;
mpfr_test_init ();
SEED_RAND (time(NULL));
N = (argc<2) ? 1000000 : atoi(argv[1]);
rnd_mode = (argc<3) ? -1 : atoi(argv[2]);
for (i=0;i<1000000;i++) {
x = drand();
y = LONG_RAND();
if (ABS(x)>2.2e-307 && x+y<1.7e+308 && x+y>-1.7e308) {
/* avoid denormalized numbers and overflows */
rnd = (rnd_mode==-1) ? LONG_RAND()%4 : rnd_mode;
check(x, y, rnd);
}
}
#endif
for (p=2; p<200; p++)
for (k=0; k<200; k++)
check_two_sum (p);
check3 (0.9999999999, 1, GMP_RNDN, -56295.0 / 562949953421312.0);
#ifdef HAVE_INFS
check3 (DBL_NAN, 1, GMP_RNDN, DBL_NAN);
check3 (DBL_POS_INF, 1, GMP_RNDN, DBL_POS_INF);
check3 (DBL_NEG_INF, 1, GMP_RNDN, DBL_NEG_INF);
#endif
return 0;
}
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