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

58 lines
1.6 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"
void
arith_bell_number_vec_recursive(fmpz * b, slong n)
{
slong i, k;
fmpz * t;
if (n < BELL_NUMBER_TAB_SIZE)
{
for (i = 0; i < n; i++)
fmpz_set_ui(b + i, bell_number_tab[i]);
return;
}
n -= 1;
t = _fmpz_vec_init(n);
fmpz_one(t);
fmpz_one(b);
fmpz_one(b + 1);
for (i = 1; i < n; i++)
{
fmpz_set(t + i, t);
for (k = i; k > 0; k--)
fmpz_add(t + k - 1, t + k - 1, t + k);
fmpz_set(b + i + 1, t);
}
_fmpz_vec_clear(t, n);
}