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random.c revision 1.1.1.1.4.2 
      1 /* random.c -- Handle seed for random numbers.
      2 
      3 // Copyright (C) 2008, 2009, 2010, 2011 INRIA
      4 
      5 This file is part of GNU MPC.
      6 
      7 GNU MPC is free software; you can redistribute it and/or modify it under
      8 the terms of the GNU Lesser General Public License as published by the
      9 Free Software Foundation; either version 3 of the License, or (at your
     10 option) any later version.
     11 
     12 GNU MPC is distributed in the hope that it will be useful, but WITHOUT ANY
     13 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
     14 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
     15 more details.
     16 
     17 You should have received a copy of the GNU Lesser General Public License
     18 along with this program. If not, see http://www.gnu.org/licenses/ .
     19 */
     20 
     21 /* Put test_start at the beginning of your test function and
     22    test_end at the end.
     23    These are an adaptation of those of MPFR. */
     24 
     25 #include "config.h"
     26 #include <stdlib.h>
     27 #include "mpc-tests.h"
     28 
     29 
     30 #ifdef TIME_WITH_SYS_TIME
     31 # include <sys/time.h>
     32 # include <time.h>
     33 #else
     34 # ifdef HAVE_SYS_TIME_H
     35 #  include <sys/time.h>
     36 # else
     37 #  include <time.h>
     38 # endif
     39 #endif
     40 
     41 gmp_randstate_t  rands;
     42 static char      rands_initialized;
     43 
     44 void
     45 test_start (void)
     46 {
     47   char *environment_seed;
     48   unsigned long seed;
     49 
     50   if (rands_initialized)
     51     {
     52       fprintf (stderr,
     53                "Put test_start at the beginning of your test function.\n");
     54       exit (1);
     55     }
     56 
     57   gmp_randinit_default (rands);
     58   rands_initialized = 1;
     59 
     60   environment_seed = getenv ("GMP_CHECK_RANDOMIZE");
     61   if (environment_seed == NULL)
     62       gmp_randseed_ui (rands, 0xfac11e);
     63   else
     64     {
     65       seed = (unsigned long int) atoi (environment_seed);
     66       if (seed == 0 || seed == 1)
     67         {
     68 #if defined HAVE_GETTIMEOFDAY
     69           struct timeval  tv;
     70           gettimeofday (&tv, NULL);
     71           seed = (unsigned long int) (tv.tv_sec + tv.tv_usec);
     72 #else
     73           time_t  tv;
     74           time (&tv);
     75           seed = (unsigned long int) tv;
     76 #endif
     77           gmp_randseed_ui (rands, seed);
     78           printf ("Seed GMP_CHECK_RANDOMIZE=%lu "
     79                   "(include this in bug reports)\n", seed);
     80         }
     81       else
     82         {
     83           printf ("Re-seeding with GMP_CHECK_RANDOMIZE=%lu\n", seed);
     84           gmp_randseed_ui (rands, seed);
     85         }
     86     }
     87 }
     88 
     89 void
     90 test_end (void)
     91 {
     92   if (rands_initialized)
     93     {
     94       rands_initialized = 0;
     95       gmp_randclear (rands);
     96     }
     97   mpfr_free_cache ();
     98 }
     99 
    100 /* Set z to a non zero value random value with absolute values of Re(z) and
    101    Im(z) either zero (but not both in the same time) or otherwise greater than
    102    or equal to 2^{emin-1} and less than 2^emax.
    103    Each part is negative with probability equal to NEGATIVE_PROBABILITY / 256.
    104    The result has one zero part (but never the two of them) with probability
    105    equal to ZERO_PROBABILITY / 256.
    106 */
    107 void
    108 test_default_random (mpc_ptr z, mpfr_exp_t emin, mpfr_exp_t emax,
    109                      unsigned int negative_probability,
    110                      unsigned int zero_probability)
    111 {
    112   const unsigned long range = (unsigned long int) (emax - emin) + 1;
    113   unsigned long r;
    114 
    115   if (!rands_initialized)
    116     {
    117       fprintf (stderr,
    118                "Put test_start at the beginning of your test function.\n");
    119       exit (1);
    120     }
    121 
    122   do
    123     {
    124       mpc_urandom (z, rands);
    125     } while (mpfr_zero_p (mpc_realref (z)) || mpfr_zero_p (mpc_imagref (z)));
    126 
    127   if (zero_probability > 256)
    128     zero_probability = 256;
    129   r = gmp_urandomb_ui (rands, 19);
    130   if ((r & 0x1FF) < zero_probability
    131       || ((r >> 9) & 0x1FF) < zero_probability)
    132     {
    133       int zero_re_p = (r & 0x1FF) < zero_probability;
    134       int zero_im_p = ((r >> 9) & 0x1FF) < zero_probability;
    135 
    136       if (zero_re_p && zero_im_p)
    137         {
    138           /* we just want one zero part. */
    139           zero_re_p = (r >> 18) & 1;
    140           zero_im_p = !zero_re_p;
    141         }
    142       if (zero_re_p)
    143         mpfr_set_ui (mpc_realref (z), 0, GMP_RNDN);
    144       if (zero_im_p)
    145         mpfr_set_ui (mpc_imagref (z), 0, GMP_RNDN);
    146     }
    147   if (!mpfr_zero_p (mpc_realref (z)))
    148     mpfr_set_exp (mpc_realref (z), (mpfr_exp_t) gmp_urandomm_ui (rands, range) + emin);
    149 
    150   if (!mpfr_zero_p (mpc_imagref (z)))
    151     mpfr_set_exp (mpc_imagref (z), (mpfr_exp_t) gmp_urandomm_ui (rands, range) + emin);
    152 
    153   if (negative_probability > 256)
    154     negative_probability = 256;
    155   r = gmp_urandomb_ui (rands, 16);
    156   if ((r & 0xFF) < negative_probability)
    157     mpfr_neg (mpc_realref (z), mpc_realref (z), GMP_RNDN);
    158   if (((r>>8) & 0xFF) < negative_probability)
    159     mpfr_neg (mpc_imagref (z), mpc_imagref (z), GMP_RNDN);
    160 }
    161