79 lines
2.1 KiB
C
79 lines
2.1 KiB
C
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/*=============================================================================
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This file is part of FLINT.
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FLINT 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 2 of the License, or
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(at your option) any later version.
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FLINT 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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You should have received a copy of the GNU General Public License
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along with FLINT; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2013 Mike Hansen
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******************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include "flint.h"
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#include "ulong_extras.h"
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mp_limb_t n_primitive_root_prime_prefactor(mp_limb_t p, n_factor_t * factors)
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{
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slong i;
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int found;
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mp_limb_t result, a, pm1;
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double pinv;
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if (p == 2)
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{
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return 1;
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}
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pm1 = p - 1;
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pinv = n_precompute_inverse(p);
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for (a = 2; a < p; a++)
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{
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found = 1;
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for (i = 0; i < factors->num; i++)
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{
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result = n_powmod_precomp(a, pm1 / factors->p[i], p, pinv);
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if (result == 1)
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{
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found = 0;
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break;
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}
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}
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if (found)
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{
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return a;
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}
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}
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flint_printf("Exception (n_primitive_root_prime_prefactor). root not found.\n");
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abort();
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}
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mp_limb_t n_primitive_root_prime(mp_limb_t p)
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{
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mp_limb_t a;
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n_factor_t factors;
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n_factor_init(&factors);
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n_factor(&factors, p - 1, 1);
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a = n_primitive_root_prime_prefactor(p, &factors);
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return a;
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}
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