1  /* Test file for mpfr_pow.
       2  
       3  Copyright 2001-2023 Free Software Foundation, Inc.
       4  Contributed by the AriC and Caramba projects, INRIA.
       5  
       6  This file is part of the GNU MPFR Library.
       7  
       8  The GNU MPFR Library is free software; you can redistribute it and/or modify
       9  it under the terms of the GNU Lesser General Public License as published by
      10  the Free Software Foundation; either version 3 of the License, or (at your
      11  option) any later version.
      12  
      13  The GNU MPFR Library is distributed in the hope that it will be useful, but
      14  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      15  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
      16  License for more details.
      17  
      18  You should have received a copy of the GNU Lesser General Public License
      19  along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
      20  https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
      21  51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
      22  
      23  #include "mpfr-test.h"
      24  
      25  
      26  int
      27  main (int argc, char *argv[])
      28  {
      29    mpfr_t x, y, z;
      30  
      31    mpfr_prec_t prec, yprec;
      32    mpfr_t t, s;
      33    mpfr_rnd_t rnd;
      34    int inexact, compare, compare2;
      35    unsigned int n, err;
      36  
      37    mpfr_prec_t p0=2, p1=100;
      38    unsigned int N=25;
      39  
      40    tests_start_mpfr ();
      41  
      42    mpfr_init (x);
      43    mpfr_init2 (y,sizeof(unsigned long int)*CHAR_BIT);
      44    mpfr_init (z);
      45  
      46    mpfr_init (s);
      47    mpfr_init (t);
      48  
      49    /* generic test */
      50    for (prec = p0; prec <= p1; prec++)
      51      {
      52        mpfr_set_prec (x, prec);
      53        mpfr_set_prec (s, sizeof(unsigned long int)*CHAR_BIT);
      54        mpfr_set_prec (z, prec);
      55        mpfr_set_prec (t, prec);
      56        yprec = prec + 10;
      57  
      58        for (n=0; n<N; n++)
      59          {
      60            mpfr_urandomb (x, RANDS);
      61            mpfr_urandomb (s, RANDS);
      62            if (RAND_BOOL ())
      63              mpfr_neg (s, s, MPFR_RNDN);
      64            rnd = RND_RAND_NO_RNDF ();
      65            mpfr_set_prec (y, yprec);
      66            compare = mpfr_pow (y, x, s, rnd);
      67            err = (rnd == MPFR_RNDN) ? yprec + 1 : yprec;
      68            if (mpfr_can_round (y, err, rnd, rnd, prec))
      69              {
      70                mpfr_set (t, y, rnd);
      71                inexact = mpfr_pow (z, x, s, rnd);
      72                if (mpfr_cmp (t, z))
      73                  {
      74                    printf ("results differ for x^y with\n");
      75                    printf ("  x=");
      76                    mpfr_dump (x);
      77                    printf ("  y=");
      78                    mpfr_dump (s);
      79                    printf ("  with prec=%u rnd_mode=%s\n", (unsigned int) prec,
      80                            mpfr_print_rnd_mode (rnd));
      81                    printf ("got      ");
      82                    mpfr_dump (z);
      83                    printf ("expected ");
      84                    mpfr_dump (t);
      85                    printf ("approx   ");
      86                    mpfr_dump (y);
      87                    exit (1);
      88                  }
      89                compare2 = mpfr_cmp (t, y);
      90                /* if rounding to nearest, cannot know the sign of t - f(x)
      91                   because of composed rounding: y = o(f(x)) and t = o(y) */
      92                if ((rnd != MPFR_RNDN) && (compare * compare2 >= 0))
      93                  compare = compare + compare2;
      94                else
      95                  compare = inexact; /* cannot determine sign(t-f(x)) */
      96                if (((inexact == 0) && (compare != 0)) ||
      97                    ((inexact > 0) && (compare <= 0)) ||
      98                    ((inexact < 0) && (compare >= 0)))
      99                  {
     100                    printf ("Wrong inexact flag for rnd=%s: expected %d, got %d"
     101                            "\n", mpfr_print_rnd_mode (rnd), compare, inexact);
     102                    printf ("x="); mpfr_dump (x);
     103                    printf ("y="); mpfr_dump (y);
     104                    printf ("t="); mpfr_dump (t);
     105                    exit (1);
     106                  }
     107              }
     108          }
     109      }
     110  
     111    mpfr_clear (s);
     112    mpfr_clear (t);
     113  
     114    mpfr_clear (x);
     115    mpfr_clear (y);
     116    mpfr_clear (z);
     117  
     118    tests_end_mpfr ();
     119    return 0;
     120  }