decimal r_rand(const decimal& min,const decimal& max)
{
#ifdef USE_CGAL
CGAL::Gmpfr m;
mpfr_urandom(m.fr(),state,MPFR_RNDN);
return r_round_preference((min>max)?decimal(m)*(min-max)+max:decimal(m)*(max-min)+min,true);
#else
return (min>max)?r_rand()*(min-max)+max:r_rand()*(max-min)+min;
#endif
}
/* Problem reported by Carl Witty. This test assumes the random generator
used by GMP is deterministic (for a given seed). We need to distinguish
two cases since the random generator changed after GMP 4.2.0. */
static void
bug20100914 (void)
{
mpfr_t x;
gmp_randstate_t s;
#if __MPFR_GMP(4,2,0)
# define C1 "0.8488312"
# define C2 "0.8156509"
#else
# define C1 "0.6485367"
# define C2 "0.9362717"
#endif
gmp_randinit_default (s);
gmp_randseed_ui (s, 42);
mpfr_init2 (x, 17);
mpfr_urandom (x, s, MPFR_RNDN);
if (mpfr_cmp_str1 (x, C1) != 0)
{
printf ("Error in bug20100914, expected " C1 ", got ");
mpfr_out_str (stdout, 10, 0, x, MPFR_RNDN);
printf ("\n");
exit (1);
}
mpfr_urandom (x, s, MPFR_RNDN);
if (mpfr_cmp_str1 (x, C2) != 0)
{
printf ("Error in bug20100914, expected " C2 ", got ");
mpfr_out_str (stdout, 10, 0, x, MPFR_RNDN);
printf ("\n");
exit (1);
}
mpfr_clear (x);
gmp_randclear (s);
}
/* check adding n random numbers, iterated k times */
static void
check_random (int n, int k, mpfr_prec_t prec, mpfr_rnd_t rnd)
{
mpfr_t *x, s, ref_s;
mpfr_ptr *y;
int i, st, ret = 0, ref_ret = 0;
gmp_randstate_t state;
gmp_randinit_default (state);
mpfr_init2 (s, prec);
mpfr_init2 (ref_s, prec);
x = (mpfr_t *) tests_allocate (n * sizeof (mpfr_t));
y = (mpfr_ptr *) tests_allocate (n * sizeof (mpfr_ptr));
for (i = 0; i < n; i++)
{
y[i] = x[i];
mpfr_init2 (x[i], prec);
mpfr_urandom (x[i], state, rnd);
}
st = cputime ();
for (i = 0; i < k; i++)
ref_ret = mpfr_sum_naive (ref_s, x, n, rnd);
printf ("mpfr_sum_naive took %dms\n", cputime () - st);
st = cputime ();
for (i = 0; i < k; i++)
ret = mpfr_sum (s, y, n, rnd);
printf ("mpfr_sum took %dms\n", cputime () - st);
if (n <= 2)
{
MPFR_ASSERTN (mpfr_cmp (ref_s, s) == 0);
MPFR_ASSERTN (ref_ret == ret);
}
for (i = 0; i < n; i++)
mpfr_clear (x[i]);
tests_free (x, n * sizeof (mpfr_t));
tests_free (y, n * sizeof (mpfr_ptr));
mpfr_clear (s);
mpfr_clear (ref_s);
gmp_randclear (state);
}
static PyObject *
GMPy_MPFR_random_Function(PyObject *self, PyObject *args)
{
MPFR_Object *result;
CTXT_Object *context = NULL;
CHECK_CONTEXT(context);
if (PyTuple_GET_SIZE(args) != 1) {
TYPE_ERROR("mpfr_random() requires 1 argument");
return NULL;
}
if (!RandomState_Check(PyTuple_GET_ITEM(args, 0))) {
TYPE_ERROR("mpfr_random() requires 'random_state' argument");
return NULL;
}
if ((result = GMPy_MPFR_New(0, context))) {
mpfr_urandom(result->f, RANDOM_STATE(PyTuple_GET_ITEM(args, 0)), GET_MPFR_ROUND(context));
}
return (PyObject*)result;
}
static void
test_urandom (long nbtests, mpfr_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;
mpfr_exp_t emin;
mp_size_t limb_index = 0;
mp_limb_t limb_mask = 0;
long count = 0;
int i;
int inex = 1;
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++)
{
i = mpfr_urandom (x, RANDS, rnd);
inex = (i != 0) && inex;
/* 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);
}
/* check that the value is in [0,1] */
if (mpfr_cmp_ui (x, 0) < 0 || mpfr_cmp_ui (x, 1) > 0)
{
printf ("Error: mpfr_urandom() returns number outside [0, 1]:\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 ++;
}
if (inex == 0)
{
/* one call in the loop pretended to return an exact number! */
printf ("Error: mpfr_urandom() returns a zero ternary value.\n");
exit (1);
}
/* coverage test */
emin = mpfr_get_emin ();
for (k = 0; k < 5; k++)
{
set_emin (k+1);
inex = mpfr_urandom (x, RANDS, rnd);
if (( (rnd == MPFR_RNDZ || rnd == MPFR_RNDD)
&& (!MPFR_IS_ZERO (x) || inex != -1))
|| ((rnd == MPFR_RNDU || rnd == MPFR_RNDA)
&& (mpfr_cmp_ui (x, 1 << k) != 0 || inex != +1))
|| (rnd == MPFR_RNDN
&& (k > 0 || mpfr_cmp_ui (x, 1 << k) != 0 || inex != +1)
&& (!MPFR_IS_ZERO (x) || inex != -1)))
{
printf ("Error: mpfr_urandom() do not handle correctly a restricted"
" exponent range.\nrounding mode: %s\nternary value: %d\n"
"random value: ", mpfr_print_rnd_mode (rnd), inex);
mpfr_print_binary (x); puts ("");
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;
}
