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

81 lines
3.1 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 "arith.h"
#define BERNOULLI_DENOM_MAX_SMALL 178
#if FLINT64
#define __u32 unsigned int
#else
#define __u32 mp_limb_t
#endif
static const __u32 __bernoulli_denom_small[] =
{
UWORD(1), UWORD(6), UWORD(30), UWORD(42), UWORD(30), UWORD(66), UWORD(2730), UWORD(6), UWORD(510), UWORD(798), UWORD(330),
UWORD(138), UWORD(2730), UWORD(6), UWORD(870), UWORD(14322), UWORD(510), UWORD(6), UWORD(1919190), UWORD(6), UWORD(13530),
UWORD(1806), UWORD(690), UWORD(282), UWORD(46410), UWORD(66), UWORD(1590), UWORD(798), UWORD(870), UWORD(354),
UWORD(56786730), UWORD(6), UWORD(510), UWORD(64722), UWORD(30), UWORD(4686), UWORD(140100870), UWORD(6), UWORD(30),
UWORD(3318), UWORD(230010), UWORD(498), UWORD(3404310), UWORD(6), UWORD(61410), UWORD(272118), UWORD(1410), UWORD(6),
UWORD(4501770), UWORD(6), UWORD(33330), UWORD(4326), UWORD(1590), UWORD(642), UWORD(209191710), UWORD(1518),
UWORD(1671270), UWORD(42), UWORD(1770), UWORD(6), UWORD(2328255930), UWORD(6), UWORD(30), UWORD(4357878), UWORD(510),
UWORD(8646), UWORD(4206930), UWORD(6), UWORD(4110), UWORD(274386), UWORD(679470), UWORD(6), UWORD(2381714790),
UWORD(6), UWORD(4470), UWORD(2162622), UWORD(30), UWORD(138), UWORD(1794590070), UWORD(6), UWORD(230010),
UWORD(130074), UWORD(2490), UWORD(1002), UWORD(3404310), UWORD(66), UWORD(5190), UWORD(2478), UWORD(1043970),
UWORD(1074),
};
void arith_bernoulli_number_denom(fmpz_t den, ulong n)
{
slong i;
mp_limb_t p;
const mp_limb_t * primes;
if (n % 2 == 1)
{
fmpz_set_ui(den, 1 + (n == 1));
}
else if (n <= BERNOULLI_DENOM_MAX_SMALL)
{
fmpz_set_ui(den, __bernoulli_denom_small[n / 2]);
}
else
{
n_prime_pi_bounds(&p, &p, n);
primes = n_primes_arr_readonly(p + 1);
fmpz_set_ui(den, UWORD(6));
for (i = 2; i < n; i++)
{
p = primes[i];
if (p - 1 > n)
break;
if (n % (p - 1) == 0)
fmpz_mul_ui(den, den, p);
}
}
}