gcc/mpfr/tests/tpow3.c

/* Test file for mpfr_pow.

Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
Contributed by the Arenaire and Cacao 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 2.1 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.LIB.  If not, write to
the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
MA 02110-1301, USA. */

#include <stdio.h>
#include <limits.h>
#include <stdlib.h>

#include "mpfr-test.h"


int
main (int argc, char *argv[])
{
  mpfr_t x, y, z;

  mp_prec_t prec, yprec;
  mpfr_t t, s;
  mp_rnd_t rnd;
  int inexact, compare, compare2;
  unsigned int n, err;

  mp_prec_t p0=2, p1=100;
  unsigned int N=25;

  tests_start_mpfr ();

  mpfr_init (x);
  mpfr_init2 (y,sizeof(unsigned long int)*CHAR_BIT);
  mpfr_init (z);

  mpfr_init (s);
  mpfr_init (t);

  /* generic test */
  for (prec = p0; prec <= p1; prec++)
    {
      mpfr_set_prec (x, prec);
      mpfr_set_prec (s, sizeof(unsigned long int)*CHAR_BIT);
      mpfr_set_prec (z, prec);
      mpfr_set_prec (t, prec);
      yprec = prec + 10;

      for (n=0; n<N; n++)
        {
          mpfr_urandomb (x, RANDS);
          mpfr_urandomb (s, RANDS);
          if (randlimb () % 2)
            mpfr_neg (s, s, GMP_RNDN);
          rnd = RND_RAND ();
          mpfr_set_prec (y, yprec);
          compare = mpfr_pow (y, x, s, rnd);
          err = (rnd == GMP_RNDN) ? yprec + 1 : yprec;
          if (mpfr_can_round (y, err, rnd, rnd, prec))
            {
              mpfr_set (t, y, rnd);
              inexact = mpfr_pow (z, x, s, rnd);
              if (mpfr_cmp (t, z))
                {
                  printf ("results differ for x^y with x=");
                  mpfr_out_str (stdout, 2, prec, x, GMP_RNDN);
                  printf (" y=");
                  mpfr_out_str (stdout, 2, 0, s, GMP_RNDN);
                  printf (" prec=%u rnd_mode=%s\n", (unsigned int) prec,
                          mpfr_print_rnd_mode (rnd));
                  printf ("got      ");
                  mpfr_out_str (stdout, 2, prec, z, GMP_RNDN);
                  puts ("");
                  printf ("expected ");
                  mpfr_out_str (stdout, 2, prec, t, GMP_RNDN);
                  puts ("");
                  printf ("approx  ");
                  mpfr_print_binary (y);
                  puts ("");
                  exit (1);
                }
              compare2 = mpfr_cmp (t, y);
              /* if rounding to nearest, cannot know the sign of t - f(x)
                 because of composed rounding: y = o(f(x)) and t = o(y) */
              if ((rnd != GMP_RNDN) && (compare * compare2 >= 0))
                compare = compare + compare2;
              else
                compare = inexact; /* cannot determine sign(t-f(x)) */
              if (((inexact == 0) && (compare != 0)) ||
                  ((inexact > 0) && (compare <= 0)) ||
                  ((inexact < 0) && (compare >= 0)))
                {
                  printf ("Wrong inexact flag for rnd=%s: expected %d, got %d"
                          "\n", mpfr_print_rnd_mode (rnd), compare, inexact);
                  printf ("x="); mpfr_print_binary (x); puts ("");
                  printf ("y="); mpfr_print_binary (y); puts ("");
                  printf ("t="); mpfr_print_binary (t); puts ("");
                  exit (1);
                }
            }
        }
    }

  mpfr_clear (s);
  mpfr_clear (t);

  mpfr_clear (x);
  mpfr_clear (y);
  mpfr_clear (z);

  tests_end_mpfr ();
  return 0;
}