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t-invert.c revision 1.1.1.3 
      1 /* Test mpz_invert.
      2 
      3 Copyright 1991, 1993, 1994, 1996, 1997, 2000-2005, 2008, 2009, 2012, 2014 Free
      4 Software Foundation, Inc.
      5 
      6 This file is part of the GNU MP Library test suite.
      7 
      8 The GNU MP Library test suite is free software; you can redistribute it
      9 and/or modify it under the terms of the GNU General Public License as
     10 published by the Free Software Foundation; either version 3 of the License,
     11 or (at your option) any later version.
     12 
     13 The GNU MP Library test suite is distributed in the hope that it will be
     14 useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
     15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
     16 Public License for more details.
     17 
     18 You should have received a copy of the GNU General Public License along with
     19 the GNU MP Library test suite.  If not, see https://www.gnu.org/licenses/.  */
     20 
     21 #include <stdio.h>
     22 #include <stdlib.h>
     23 
     24 #include "gmp-impl.h"
     25 #include "tests.h"
     26 
     27 int
     28 main (int argc, char **argv)
     29 {
     30   mpz_t a, m, ainv, t;
     31   int test, r;
     32   gmp_randstate_ptr rands;
     33   mpz_t bs;
     34   unsigned long bsi, size_range;
     35   int reps = 1000;
     36 
     37   tests_start ();
     38   TESTS_REPS (reps, argv, argc);
     39 
     40   rands = RANDS;
     41 
     42   mpz_init (bs);
     43   mpz_init (a);
     44   mpz_init (m);
     45   mpz_init (ainv);
     46   mpz_init (t);
     47 
     48   for (test = 0; test < reps; test++)
     49     {
     50       mpz_urandomb (bs, rands, 32);
     51       size_range = mpz_get_ui (bs) % 16 + 2;
     52 
     53       mpz_urandomb (bs, rands, size_range);
     54       mpz_rrandomb (a, rands, mpz_get_ui (bs));
     55       do {
     56 	mpz_urandomb (bs, rands, size_range);
     57 	mpz_rrandomb (m, rands, mpz_get_ui (bs));
     58       } while (mpz_sgn (m) == 0);
     59 
     60       mpz_urandomb (bs, rands, 8);
     61       bsi = mpz_get_ui (bs);
     62 
     63       if ((bsi & 1) != 0)
     64 	mpz_neg (a, a);
     65       if ((bsi & 2) != 0)
     66 	mpz_neg (m, m);
     67 
     68       r = mpz_invert (ainv, a, m);
     69       if (r != 0)
     70 	{
     71 	  MPZ_CHECK_FORMAT (ainv);
     72 
     73 	  if (mpz_cmp_ui (ainv, 0) < 0 || mpz_cmpabs (ainv, m) >= 0)
     74 	    {
     75 	      fprintf (stderr, "ERROR in test %d\n", test);
     76 	      gmp_fprintf (stderr, "Inverse out of range.\n");
     77 	      gmp_fprintf (stderr, "a = %Zx\n", a);
     78 	      gmp_fprintf (stderr, "1/a = %Zx\n", ainv);
     79 	      gmp_fprintf (stderr, "m = %Zx\n", m);
     80 	      abort ();
     81 	    }
     82 
     83 	  mpz_mul (t, ainv, a);
     84 	  mpz_mod (t, t, m);
     85 
     86 	  if (mpz_cmp_ui (t, mpz_cmpabs_ui (m, 1) != 0) != 0)
     87 	    {
     88 	      fprintf (stderr, "ERROR in test %d\n", test);
     89 	      gmp_fprintf (stderr, "a^(-1)*a != 1 (mod m)\n");
     90 	      gmp_fprintf (stderr, "a = %Zx\n", a);
     91 	      gmp_fprintf (stderr, "m = %Zx\n", m);
     92 	      abort ();
     93 	    }
     94 	}
     95       else /* Inverse deos not exist */
     96 	{
     97 	  mpz_gcd (t, a, m);
     98 	  if (mpz_cmp_ui (t, 1) == 0)
     99 	    {
    100 	      fprintf (stderr, "ERROR in test %d\n", test);
    101 	      gmp_fprintf (stderr, "Inverse exists, but was not found.\n");
    102 	      gmp_fprintf (stderr, "a = %Zx\n", a);
    103 	      gmp_fprintf (stderr, "m = %Zx\n", m);
    104 	      abort ();
    105 	    }
    106 	}
    107     }
    108 
    109   mpz_clear (bs);
    110   mpz_clear (a);
    111   mpz_clear (m);
    112   mpz_clear (ainv);
    113   mpz_clear (t);
    114 
    115   tests_end ();
    116   exit (0);
    117 }
    118