pqc/external/flint-2.4.3/ulong_extras/test/t-factorial_mod2_preinv.c
2014-05-24 23:16:06 +02:00

81 lines
2.1 KiB
C

/*=============================================================================
This file is part of FLINT.
FLINT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FLINT 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2011 Fredrik Johansson
******************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include "flint.h"
#include "ulong_extras.h"
static mp_limb_t
n_factorial_mod2_foolproof(ulong n, mp_limb_t p, mp_limb_t pinv)
{
mp_limb_t prod = UWORD(1) % p;
while (n)
{
prod = n_mulmod2_preinv(prod, n, p, pinv);
n--;
}
return prod;
}
int main(void)
{
mp_limb_t n;
int j;
FLINT_TEST_INIT(state);
flint_printf("factorial_mod2_preinv....");
fflush(stdout);
for (n = 0; n < 100 * flint_test_multiplier(); n++)
{
mp_limb_t p, pinv, x, y;
for (j = 0; j < 10; j++)
{
p = n_randtest_not_zero(state);
pinv = n_preinvert_limb(p);
x = n_factorial_mod2_preinv(n, p, pinv);
y = n_factorial_mod2_foolproof(n, p, pinv);
if (x != y)
{
flint_printf("FAIL:\n");
flint_printf("n = %wu\np = %wu\nx = %wu\ny = %wu\n", n, p, x, y);
abort();
}
}
}
FLINT_TEST_CLEANUP(state);
flint_printf("PASS\n");
return 0;
}