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/* Test mpz_perfect_square_p.
Copyright 2000, 2001, 2002 Free Software Foundation, Inc.
This file is part of the GNU MP Library.
The GNU MP 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 MP 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 MP Library. If not, see http://www.gnu.org/licenses/. */
#include <stdio.h>
#include <stdlib.h>
#include "gmp.h"
#include "gmp-impl.h"
#include "tests.h"
#include "mpn/perfsqr.h"
/* check_modulo() exercises mpz_perfect_square_p on squares which cover each
possible quadratic residue to each divisor used within
mpn_perfect_square_p, ensuring those residues aren't incorrectly claimed
to be non-residues.
Each divisor is taken separately. It's arranged that n is congruent to 0
modulo the other divisors, 0 of course being a quadratic residue to any
modulus.
The values "(j*others)^2" cover all quadratic residues mod divisor[i],
but in no particular order. j is run from 1<=j<=divisor[i] so that zero
is excluded. A literal n==0 doesn't reach the residue tests. */
void
check_modulo (void)
{
static const unsigned long divisor[] = PERFSQR_DIVISORS;
unsigned long i, j;
mpz_t alldiv, others, n;
mpz_init (alldiv);
mpz_init (others);
mpz_init (n);
/* product of all divisors */
mpz_set_ui (alldiv, 1L);
for (i = 0; i < numberof (divisor); i++)
mpz_mul_ui (alldiv, alldiv, divisor[i]);
for (i = 0; i < numberof (divisor); i++)
{
/* product of all divisors except i */
mpz_set_ui (others, 1L);
for (j = 0; j < numberof (divisor); j++)
if (i != j)
mpz_mul_ui (others, others, divisor[j]);
for (j = 1; j <= divisor[i]; j++)
{
/* square */
mpz_mul_ui (n, others, j);
mpz_mul (n, n, n);
if (! mpz_perfect_square_p (n))
{
printf ("mpz_perfect_square_p got 0, want 1\n");
mpz_trace (" n", n);
abort ();
}
}
}
mpz_clear (alldiv);
mpz_clear (others);
mpz_clear (n);
}
/* Exercise mpz_perfect_square_p compared to what mpz_sqrt says. */
void
check_sqrt (int reps)
{
mpz_t x2, x2t, x;
mp_size_t x2n;
int res;
int i;
/* int cnt = 0; */
gmp_randstate_ptr rands = RANDS;
mpz_t bs;
mpz_init (bs);
mpz_init (x2);
mpz_init (x);
mpz_init (x2t);
for (i = 0; i < reps; i++)
{
mpz_urandomb (bs, rands, 9);
x2n = mpz_get_ui (bs);
mpz_rrandomb (x2, rands, x2n);
/* mpz_out_str (stdout, -16, x2); puts (""); */
res = mpz_perfect_square_p (x2);
mpz_sqrt (x, x2);
mpz_mul (x2t, x, x);
if (res != (mpz_cmp (x2, x2t) == 0))
{
printf ("mpz_perfect_square_p and mpz_sqrt differ\n");
mpz_trace (" x ", x);
mpz_trace (" x2 ", x2);
mpz_trace (" x2t", x2t);
printf (" mpz_perfect_square_p %d\n", res);
printf (" mpz_sqrt %d\n", mpz_cmp (x2, x2t) == 0);
abort ();
}
/* cnt += res != 0; */
}
/* printf ("%d/%d perfect squares\n", cnt, reps); */
mpz_clear (bs);
mpz_clear (x2);
mpz_clear (x);
mpz_clear (x2t);
}
int
main (int argc, char **argv)
{
int reps = 100000;
tests_start ();
mp_trace_base = -16;
if (argc == 2)
reps = atoi (argv[1]);
check_modulo ();
check_sqrt (reps);
tests_end ();
exit (0);
}
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