pqc/external/flint-2.4.3/fmpz_poly/taylor_shift_horner.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) 2012 Fredrik Johansson
******************************************************************************/
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_poly.h"
void
_fmpz_poly_taylor_shift_horner(fmpz * poly, const fmpz_t c, slong n)
{
slong i, j;
if (*c == WORD(1))
{
for (i = n - 2; i >= 0; i--)
for (j = i; j < n - 1; j++)
fmpz_add(poly + j, poly + j, poly + j + 1);
}
else if (*c == WORD(-1))
{
for (i = n - 2; i >= 0; i--)
for (j = i; j < n - 1; j++)
fmpz_sub(poly + j, poly + j, poly + j + 1);
}
else if (*c != WORD(0))
{
for (i = n - 2; i >= 0; i--)
for (j = i; j < n - 1; j++)
fmpz_addmul(poly + j, poly + j + 1, c);
}
}
void
fmpz_poly_taylor_shift_horner(fmpz_poly_t g, const fmpz_poly_t f,
const fmpz_t c)
{
if (f != g)
fmpz_poly_set(g, f);
_fmpz_poly_taylor_shift_horner(g->coeffs, c, g->length);
}