t-pprime_p.c
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上传日期:2022-08-06
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- /* Exercise mpz_probab_prime_p.
- Copyright 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"
- /* Enhancements:
- - Test some big primes don't come back claimed to be composite.
- - Test some big composites don't come back claimed to be certainly prime.
- - Test some big composites with small factors are identified as certainly
- composite. */
- /* return 1 if prime, 0 if composite */
- int
- isprime (long n)
- {
- long i;
- n = ABS(n);
- if (n < 2)
- return 0;
- if (n == 2)
- return 1;
- if ((n & 1) == 0)
- return 0;
- for (i = 3; i < n; i++)
- if ((n % i) == 0)
- return 0;
- return 1;
- }
- void
- check_one (mpz_srcptr n, int want)
- {
- int got;
- got = mpz_probab_prime_p (n, 25);
- /* "definitely prime" is fine if we only wanted "probably prime" */
- if (got == 2 && want == 1)
- want = 2;
- if (got != want)
- {
- printf ("mpz_probab_prime_pn");
- mpz_trace (" n ", n);
- printf (" got =%d", got);
- printf (" want=%d", want);
- abort ();
- }
- }
- void
- check_pn (mpz_ptr n, int want)
- {
- check_one (n, want);
- mpz_neg (n, n);
- check_one (n, want);
- }
- /* expect certainty for small n */
- void
- check_small (void)
- {
- mpz_t n;
- long i;
- mpz_init (n);
- for (i = 0; i < 300; i++)
- {
- mpz_set_si (n, i);
- check_pn (n, isprime (i));
- }
- mpz_clear (n);
- }
- int
- main (void)
- {
- tests_start ();
- check_small ();
- tests_end ();
- exit (0);
- }