pqc/external/flint-2.4.3/arith/number_of_partitions_nmod_vec.c

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2014-05-18 22:03:37 +00:00
/*=============================================================================
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"
void
arith_number_of_partitions_nmod_vec(mp_ptr res, slong len, nmod_t mod)
{
mp_ptr tmp;
mp_limb_t r;
slong k, n;
r = mod.n - UWORD(1);
if (len < 1)
return;
tmp = _nmod_vec_init(len);
_nmod_vec_zero(tmp, len);
tmp[0] = UWORD(1);
for (n = k = 1; n + 4*k + 2 < len; k += 2)
{
tmp[n] = r;
tmp[n + k] = r;
tmp[n + 3*k + 1] = UWORD(1);
tmp[n + 4*k + 2] = UWORD(1);
n += 6*k + 5;
}
if (n < len) tmp[n] = r;
if (n + k < len) tmp[n + k] = r;
if (n + 3*k + 1 < len) tmp[n + 3*k + 1] = WORD(1);
_nmod_poly_inv_series(res, tmp, len, mod);
_nmod_vec_clear(tmp);
}