pqc/external/flint-2.4.3/fmpz_mod_poly/sub.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 Sebastian Pancratz
Copyright (C) 2008, 2009 William Hart
******************************************************************************/
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_poly.h"
#include "fmpz_mod_poly.h"
void _fmpz_mod_poly_sub(fmpz *res, const fmpz *poly1, slong len1,
const fmpz *poly2, slong len2, const fmpz_t p)
{
slong i, len = FLINT_MAX(len1, len2);
_fmpz_poly_sub(res, poly1, len1, poly2, len2);
for (i = 0; i < len; i++)
{
if (fmpz_sgn(res + i) < 0)
fmpz_add(res + i, res + i, p);
}
}
void fmpz_mod_poly_sub(fmpz_mod_poly_t res,
const fmpz_mod_poly_t poly1, const fmpz_mod_poly_t poly2)
{
slong max = FLINT_MAX(poly1->length, poly2->length);
fmpz_mod_poly_fit_length(res, max);
_fmpz_mod_poly_sub(res->coeffs, poly1->coeffs, poly1->length,
poly2->coeffs, poly2->length, &(res->p));
_fmpz_mod_poly_set_length(res, max);
_fmpz_mod_poly_normalise(res);
}