1/* Test file for mpfr_urandom
2
3Copyright 1999, 2000, 2001, 2002, 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
4Contributed by the Arenaire and Cacao projects, INRIA.
5
6This file is part of the GNU MPFR Library.
7
8The GNU MPFR Library is free software; you can redistribute it and/or modify
9it under the terms of the GNU Lesser General Public License as published by
10the Free Software Foundation; either version 3 of the License, or (at your
11option) any later version.
12
13The GNU MPFR Library is distributed in the hope that it will be useful, but
14WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
15or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
16License for more details.
17
18You should have received a copy of the GNU Lesser General Public License
19along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
20http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
2151 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
22
23#include <stdio.h>
24#include <stdlib.h>
25
26#include "mpfr-test.h"
27
28static void
29test_urandom (long nbtests, mpfr_prec_t prec, mpfr_rnd_t rnd, long bit_index,
30              int verbose)
31{
32  mpfr_t x;
33  int *tab, size_tab, k, sh, xn;
34  double d, av = 0, var = 0, chi2 = 0, th;
35  mpfr_exp_t emin;
36  mp_size_t limb_index = 0;
37  mp_limb_t limb_mask = 0;
38  long count = 0;
39  int i;
40  int inex = 1;
41
42  size_tab = (nbtests >= 1000 ? nbtests / 50 : 20);
43  tab = (int *) calloc (size_tab, sizeof(int));
44  if (tab == NULL)
45    {
46      fprintf (stderr, "trandom: can't allocate memory in test_urandom\n");
47      exit (1);
48    }
49
50  mpfr_init2 (x, prec);
51  xn = 1 + (prec - 1) / mp_bits_per_limb;
52  sh = xn * mp_bits_per_limb - prec;
53  if (bit_index >= 0 && bit_index < prec)
54    {
55      /* compute the limb index and limb mask to fetch the bit #bit_index */
56      limb_index = (prec - bit_index) / mp_bits_per_limb;
57      i = 1 + bit_index - (bit_index / mp_bits_per_limb) * mp_bits_per_limb;
58      limb_mask = MPFR_LIMB_ONE << (mp_bits_per_limb - i);
59    }
60
61  for (k = 0; k < nbtests; k++)
62    {
63      i = mpfr_urandom (x, RANDS, rnd);
64      inex = (i != 0) && inex;
65      /* check that lower bits are zero */
66      if (MPFR_MANT(x)[0] & MPFR_LIMB_MASK(sh) && !MPFR_IS_ZERO (x))
67        {
68          printf ("Error: mpfr_urandom() returns invalid numbers:\n");
69          mpfr_print_binary (x); puts ("");
70          exit (1);
71        }
72      /* check that the value is in [0,1] */
73      if (mpfr_cmp_ui (x, 0) < 0 || mpfr_cmp_ui (x, 1) > 0)
74        {
75          printf ("Error: mpfr_urandom() returns number outside [0, 1]:\n");
76          mpfr_print_binary (x); puts ("");
77          exit (1);
78        }
79
80      d = mpfr_get_d1 (x); av += d; var += d*d;
81      i = (int)(size_tab * d);
82      if (d == 1.0) i --;
83      tab[i]++;
84
85      if (limb_mask && (MPFR_MANT (x)[limb_index] & limb_mask))
86        count ++;
87    }
88
89  if (inex == 0)
90    {
91      /* one call in the loop pretended to return an exact number! */
92      printf ("Error: mpfr_urandom() returns a zero ternary value.\n");
93      exit (1);
94    }
95
96  /* coverage test */
97  emin = mpfr_get_emin ();
98  for (k = 0; k < 5; k++)
99    {
100      set_emin (k+1);
101      inex = mpfr_urandom (x, RANDS, rnd);
102      if ((   (rnd == MPFR_RNDZ || rnd == MPFR_RNDD)
103              && (!MPFR_IS_ZERO (x) || inex != -1))
104          || ((rnd == MPFR_RNDU || rnd == MPFR_RNDA)
105              && (mpfr_cmp_ui (x, 1 << k) != 0 || inex != +1))
106          || (rnd == MPFR_RNDN
107              && (k > 0 || mpfr_cmp_ui (x, 1 << k) != 0 || inex != +1)
108              && (!MPFR_IS_ZERO (x) || inex != -1)))
109        {
110          printf ("Error: mpfr_urandom() do not handle correctly a restricted"
111                  " exponent range.\nrounding mode: %s\nternary value: %d\n"
112                  "random value: ", mpfr_print_rnd_mode (rnd), inex);
113          mpfr_print_binary (x); puts ("");
114          exit (1);
115        }
116    }
117  set_emin (emin);
118
119  mpfr_clear (x);
120  if (!verbose)
121    {
122      free(tab);
123      return;
124    }
125
126  av /= nbtests;
127  var = (var / nbtests) - av * av;
128
129  th = (double)nbtests / size_tab;
130  printf ("Average = %.5f\nVariance = %.5f\n", av, var);
131  printf ("Repartition for urandom with rounding mode %s. "
132          "Each integer should be close to %d.\n",
133         mpfr_print_rnd_mode (rnd), (int)th);
134
135  for (k = 0; k < size_tab; k++)
136    {
137      chi2 += (tab[k] - th) * (tab[k] - th) / th;
138      printf("%d ", tab[k]);
139      if (((k+1) & 7) == 0)
140        printf("\n");
141    }
142
143  printf("\nChi2 statistics value (with %d degrees of freedom) : %.5f\n",
144         size_tab - 1, chi2);
145
146  if (limb_mask)
147    printf ("Bit #%ld is set %ld/%ld = %.1f %% of time\n",
148            bit_index, count, nbtests, count * 100.0 / nbtests);
149
150  puts ("");
151
152  free(tab);
153  return;
154}
155
156
157int
158main (int argc, char *argv[])
159{
160  long nbtests;
161  mpfr_prec_t prec;
162  int verbose = 0;
163  int rnd;
164  long bit_index;
165
166  tests_start_mpfr ();
167
168  if (argc > 1)
169    verbose = 1;
170
171  nbtests = 10000;
172  if (argc > 1)
173    {
174      long a = atol(argv[1]);
175      if (a != 0)
176        nbtests = a;
177    }
178
179  if (argc <= 2)
180    prec = 1000;
181  else
182    prec = atol(argv[2]);
183
184  if (argc <= 3)
185    bit_index = -1;
186  else
187    {
188      bit_index = atol(argv[3]);
189      if (bit_index >= prec)
190        {
191          printf ("Warning. Cannot compute the bit frequency: the given bit "
192                  "index (= %ld) is not less than the precision (= %ld).\n",
193                  bit_index, prec);
194          bit_index = -1;
195        }
196    }
197
198  RND_LOOP(rnd)
199    {
200      test_urandom (nbtests, prec, (mpfr_rnd_t) rnd, bit_index, verbose);
201
202      if (argc == 1)  /* check also small precision */
203        {
204          test_urandom (nbtests, 2, (mpfr_rnd_t) rnd, -1, 0);
205        }
206    }
207
208  tests_end_mpfr ();
209  return 0;
210}
211