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

62 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) 2012 Fredrik Johansson
******************************************************************************/
#include "flint.h"
#include "nmod_poly.h"
void
_nmod_poly_taylor_shift_horner(mp_ptr poly, mp_limb_t c, slong n, nmod_t mod)
{
slong i, j;
if (c == 1)
{
for (i = n - 2; i >= 0; i--)
for (j = i; j < n - 1; j++)
poly[j] = nmod_add(poly[j], poly[j + 1], mod);
}
else if (c == mod.n - 1)
{
for (i = n - 2; i >= 0; i--)
for (j = i; j < n - 1; j++)
poly[j] = nmod_sub(poly[j], poly[j + 1], mod);
}
else if (c != 0)
{
for (i = n - 2; i >= 0; i--)
for (j = i; j < n - 1; j++)
NMOD_ADDMUL(poly[j], poly[j + 1], c, mod);
}
}
void
nmod_poly_taylor_shift_horner(nmod_poly_t g, const nmod_poly_t f, mp_limb_t c)
{
if (f != g)
nmod_poly_set(g, f);
_nmod_poly_taylor_shift_horner(g->coeffs, c, g->length, g->mod);
}