pqc/external/flint-2.4.3/fmpz/fac_ui.c
2014-05-24 23:16:06 +02:00

57 lines
1.9 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) 2010 Fredrik Johansson
******************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "ulong_extras.h"
#include "fmpz.h"
#if FLINT64
#define FLINT_NUM_TINY_FACTORIALS 21
#else
#define FLINT_NUM_TINY_FACTORIALS 13
#endif
const mp_limb_t flint_tiny_factorials[] =
{
UWORD(1), UWORD(1), UWORD(2), UWORD(6), UWORD(24), UWORD(120), UWORD(720), UWORD(5040), UWORD(40320), UWORD(362880),
UWORD(3628800), UWORD(39916800), UWORD(479001600),
#if FLINT64
UWORD(6227020800), UWORD(87178291200), UWORD(1307674368000), UWORD(20922789888000),
UWORD(355687428096000), UWORD(6402373705728000), UWORD(121645100408832000),
UWORD(2432902008176640000),
#endif
};
void fmpz_fac_ui(fmpz_t f, ulong n)
{
if (n < FLINT_NUM_TINY_FACTORIALS)
fmpz_set_ui(f, flint_tiny_factorials[n]);
else
flint_mpz_fac_ui(_fmpz_promote(f), n);
}