t-perfsqr.c
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上传日期:2022-08-06
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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 1n");
- 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 differn");
- mpz_trace (" x ", x);
- mpz_trace (" x2 ", x2);
- mpz_trace (" x2t", x2t);
- printf (" mpz_perfect_square_p %dn", res);
- printf (" mpz_sqrt %dn", mpz_cmp (x2, x2t) == 0);
- abort ();
- }
- /* cnt += res != 0; */
- }
- /* printf ("%d/%d perfect squaresn", cnt, reps); */
- mpz_clear (bs);
- mpz_clear (x2);
- mpz_clear (x);
- mpz_clear (x2t);
- }
- int
- main (int argc, char **argv)
- {
- int reps = 200000;
- tests_start ();
- mp_trace_base = -16;
- if (argc == 2)
- reps = atoi (argv[1]);
- check_modulo ();
- check_sqrt (reps);
- tests_end ();
- exit (0);
- }