New function mpfr_urandom.

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@6654 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 187 insertions, 0 deletions

diff --git a/tests/turandom.c b/tests/turandom.c
new file mode 100644
index 000000000..7c3af4595
--- /dev/null
+++ b/tests/turandom.c
@@ -0,0 +1,187 @@
+/* Test file for mpfr_urandom
+
+Copyright 1999, 2000, 2001, 2002, 2003, 2004, 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 3 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.LESSER.  If not, see
+http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
+51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "mpfr-test.h"
+
+static void
+test_urandom (long nbtests, mp_prec_t prec, mpfr_rnd_t rnd, long bit_index,
+              int verbose)
+{
+  mpfr_t x;
+  int *tab, size_tab, k, sh, xn;
+  double d, av = 0, var = 0, chi2 = 0, th;
+  mp_exp_t emin;
+  mp_size_t limb_index = 0;
+  mp_limb_t limb_mask = 0;
+  long count = 0;
+  int i;
+
+  size_tab = (nbtests >= 1000 ? nbtests / 50 : 20);
+  tab = (int *) calloc (size_tab, sizeof(int));
+  if (tab == NULL)
+    {
+      fprintf (stderr, "trandom: can't allocate memory in test_urandom\n");
+      exit (1);
+    }
+
+  mpfr_init2 (x, prec);
+  xn = 1 + (prec - 1) / mp_bits_per_limb;
+  sh = xn * mp_bits_per_limb - prec;
+  if (bit_index >= 0 && bit_index < prec)
+    {
+      /* compute the limb index and limb mask to fetch the bit #bit_index */
+      limb_index = (prec - bit_index) / mp_bits_per_limb;
+      i = 1 + bit_index - (bit_index / mp_bits_per_limb) * mp_bits_per_limb;
+      limb_mask = MPFR_LIMB_ONE << (mp_bits_per_limb - i);
+    }
+
+  for (k = 0; k < nbtests; k++)
+    {
+      mpfr_urandom (x, RANDS, rnd);
+      /* check that lower bits are zero */
+      if (MPFR_MANT(x)[0] & MPFR_LIMB_MASK(sh) && !MPFR_IS_ZERO (x))
+        {
+          printf ("Error: mpfr_urandom() returns invalid numbers:\n");
+          mpfr_print_binary (x); puts ("");
+          exit (1);
+        }
+      d = mpfr_get_d1 (x); av += d; var += d*d;
+      i = (int)(size_tab * d);
+      if (d == 1.0) i --;
+      tab[i]++;
+
+      if (limb_mask && (MPFR_MANT (x)[limb_index] & limb_mask))
+        count ++;
+    }
+
+  /* coverage test */
+  emin = mpfr_get_emin ();
+  set_emin (1);
+  /* the generated number in [0,1] is not in the exponent range, except:
+     - if it is zero and rnd is toward zero or to nearest
+     - if it is one and rnd is not toward zero and not to nearest */
+  k = mpfr_urandom (x, RANDS, rnd);
+  if ((k == 0 || mpfr_nan_p (x) == 0)
+      && (((rnd != MPFR_RNDZ && rnd != MPFR_RNDN) && MPFR_IS_ZERO (x))
+          || ((rnd==MPFR_RNDZ || rnd==MPFR_RNDN) && mpfr_cmp_ui (x, 1)==0)))
+    {
+      printf ("Error in mpfr_urandom, expected NaN, got ");
+      mpfr_dump (x);
+      exit (1);
+    }
+  set_emin (emin);
+
+  mpfr_clear (x);
+  if (!verbose)
+    {
+      free(tab);
+      return;
+    }
+
+  av /= nbtests;
+  var = (var / nbtests) - av * av;
+
+  th = (double)nbtests / size_tab;
+  printf("Average = %.5f\nVariance = %.5f\n", av, var);
+  printf("Repartition for urandom with rounding mode %s. "
+         "Each integer should be close to %d.\n",
+         mpfr_print_rnd_mode (rnd), (int)th);
+
+  for (k = 0; k < size_tab; k++)
+    {
+      chi2 += (tab[k] - th) * (tab[k] - th) / th;
+      printf("%d ", tab[k]);
+      if (((k+1) & 7) == 0)
+        printf("\n");
+    }
+
+  printf("\nChi2 statistics value (with %d degrees of freedom) : %.5f\n",
+         size_tab - 1, chi2);
+
+  if (limb_mask)
+    printf ("Bit #%ld is set %ld/%ld = %.1f %% of time\n",
+            bit_index, count, nbtests, count * 100.0 / nbtests);
+
+  puts ("");
+
+  free(tab);
+  return;
+}
+
+
+int
+main (int argc, char *argv[])
+{
+  long nbtests;
+  mp_prec_t prec;
+  int verbose = 0;
+  mpfr_rnd_t rnd;
+  long bit_index;
+
+  tests_start_mpfr ();
+
+  if (argc > 1)
+    verbose = 1;
+
+  nbtests = 10000;
+  if (argc > 1)
+    {
+      long a = atol(argv[1]);
+      if (a != 0)
+        nbtests = a;
+    }
+
+  if (argc <= 2)
+    prec = 1000;
+  else
+    prec = atol(argv[2]);
+
+  if (argc <= 3)
+    bit_index = -1;
+  else
+    {
+      bit_index = atol(argv[3]);
+      if (bit_index >= prec)
+        {
+          printf ("Warning. Cannot compute the bit frequency: the given bit "
+                  "index (= %ld) is not less than the precision (= %ld).\n",
+                  bit_index, prec);
+          bit_index = -1;
+        }
+    }
+
+  RND_LOOP(rnd)
+    {
+      test_urandom (nbtests, prec, rnd, bit_index, verbose);
+
+      if (argc == 1)  /* check also small precision */
+        {
+          test_urandom (nbtests, 2, rnd, -1, 0);
+        }
+    }
+
+  tests_end_mpfr ();
+  return 0;
+}