81 lines
2.1 KiB
C
81 lines
2.1 KiB
C
/*=============================================================================
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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) 2011 Fredrik Johansson
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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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static mp_limb_t
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n_factorial_mod2_foolproof(ulong n, mp_limb_t p, mp_limb_t pinv)
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{
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mp_limb_t prod = UWORD(1) % p;
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while (n)
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{
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prod = n_mulmod2_preinv(prod, n, p, pinv);
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n--;
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}
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return prod;
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}
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int main(void)
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{
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mp_limb_t n;
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int j;
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FLINT_TEST_INIT(state);
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flint_printf("factorial_mod2_preinv....");
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fflush(stdout);
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for (n = 0; n < 100 * flint_test_multiplier(); n++)
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{
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mp_limb_t p, pinv, x, y;
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for (j = 0; j < 10; j++)
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{
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p = n_randtest_not_zero(state);
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pinv = n_preinvert_limb(p);
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x = n_factorial_mod2_preinv(n, p, pinv);
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y = n_factorial_mod2_foolproof(n, p, pinv);
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if (x != y)
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{
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flint_printf("FAIL:\n");
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flint_printf("n = %wu\np = %wu\nx = %wu\ny = %wu\n", n, p, x, y);
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abort();
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}
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}
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}
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FLINT_TEST_CLEANUP(state);
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flint_printf("PASS\n");
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return 0;
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}
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