155 lines
3.8 KiB
C
155 lines
3.8 KiB
C
/* Test mpz_perfect_square_p.
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Copyright 2000-2002 Free Software Foundation, Inc.
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This file is part of the GNU MP Library test suite.
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The GNU MP Library test suite is free software; you can redistribute it
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and/or modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 3 of the License,
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or (at your option) any later version.
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The GNU MP Library test suite is distributed in the hope that it will be
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useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
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Public License for more details.
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You should have received a copy of the GNU General Public License along with
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the GNU MP Library test suite. If not, see https://www.gnu.org/licenses/. */
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#include <stdio.h>
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#include <stdlib.h>
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#include "gmp-impl.h"
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#include "tests.h"
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#include "mpn/perfsqr.h"
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/* check_modulo() exercises mpz_perfect_square_p on squares which cover each
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possible quadratic residue to each divisor used within
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mpn_perfect_square_p, ensuring those residues aren't incorrectly claimed
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to be non-residues.
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Each divisor is taken separately. It's arranged that n is congruent to 0
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modulo the other divisors, 0 of course being a quadratic residue to any
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modulus.
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The values "(j*others)^2" cover all quadratic residues mod divisor[i],
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but in no particular order. j is run from 1<=j<=divisor[i] so that zero
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is excluded. A literal n==0 doesn't reach the residue tests. */
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void
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check_modulo (void)
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{
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static const unsigned long divisor[] = PERFSQR_DIVISORS;
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unsigned long i, j;
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mpz_t alldiv, others, n;
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mpz_init (alldiv);
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mpz_init (others);
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mpz_init (n);
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/* product of all divisors */
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mpz_set_ui (alldiv, 1L);
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for (i = 0; i < numberof (divisor); i++)
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mpz_mul_ui (alldiv, alldiv, divisor[i]);
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for (i = 0; i < numberof (divisor); i++)
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{
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/* product of all divisors except i */
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mpz_set_ui (others, 1L);
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for (j = 0; j < numberof (divisor); j++)
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if (i != j)
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mpz_mul_ui (others, others, divisor[j]);
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for (j = 1; j <= divisor[i]; j++)
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{
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/* square */
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mpz_mul_ui (n, others, j);
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mpz_mul (n, n, n);
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if (! mpz_perfect_square_p (n))
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{
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printf ("mpz_perfect_square_p got 0, want 1\n");
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mpz_trace (" n", n);
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abort ();
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}
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}
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}
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mpz_clear (alldiv);
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mpz_clear (others);
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mpz_clear (n);
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}
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/* Exercise mpz_perfect_square_p compared to what mpz_sqrt says. */
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void
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check_sqrt (int reps)
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{
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mpz_t x2, x2t, x;
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mp_size_t x2n;
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int res;
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int i;
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/* int cnt = 0; */
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gmp_randstate_ptr rands = RANDS;
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mpz_t bs;
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mpz_init (bs);
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mpz_init (x2);
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mpz_init (x);
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mpz_init (x2t);
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for (i = 0; i < reps; i++)
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{
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mpz_urandomb (bs, rands, 9);
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x2n = mpz_get_ui (bs);
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mpz_rrandomb (x2, rands, x2n);
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/* mpz_out_str (stdout, -16, x2); puts (""); */
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res = mpz_perfect_square_p (x2);
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mpz_sqrt (x, x2);
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mpz_mul (x2t, x, x);
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if (res != (mpz_cmp (x2, x2t) == 0))
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{
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printf ("mpz_perfect_square_p and mpz_sqrt differ\n");
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mpz_trace (" x ", x);
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mpz_trace (" x2 ", x2);
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mpz_trace (" x2t", x2t);
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printf (" mpz_perfect_square_p %d\n", res);
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printf (" mpz_sqrt %d\n", mpz_cmp (x2, x2t) == 0);
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abort ();
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}
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/* cnt += res != 0; */
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}
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/* printf ("%d/%d perfect squares\n", cnt, reps); */
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mpz_clear (bs);
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mpz_clear (x2);
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mpz_clear (x);
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mpz_clear (x2t);
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}
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int
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main (int argc, char **argv)
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{
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int reps = 200000;
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tests_start ();
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mp_trace_base = -16;
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if (argc == 2)
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reps = atoi (argv[1]);
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check_modulo ();
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check_sqrt (reps);
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tests_end ();
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exit (0);
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}
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