Nicolás Ortega Froysa
84687f86c1
I recently found out that `p` being prime, while `p > 3`, then `p = 6*k (+/-) 1`.
40 lines
1.1 KiB
C
40 lines
1.1 KiB
C
/*
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* Copyright (C) 2019 Ortega Froysa, Nicolás <nicolas@ortegas.org>
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* Author: Ortega Froysa, Nicolás <nicolas@ortegas.org>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "prime_test.h"
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int test_prime(const mpz_t p) {
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mpz_t psqrt;
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mpz_t aux;
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mpz_inits(psqrt, aux, NULL);
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mpz_sqrt(psqrt, p);
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int is_prime = 1;
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for(mpz_set_ui(aux, 5); mpz_cmp(aux, psqrt) <= 0; mpz_add_ui(aux, aux, 2))
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{
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if(mpz_divisible_p(p, aux))
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{
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is_prime = 0;
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break;
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}
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}
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mpz_clears(psqrt, aux, NULL);
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return is_prime;
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}
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