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