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

65 lines
2.0 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, 2012 Sebastian Pancratz
******************************************************************************/
#include "fmpz_mod_poly.h"
#include "padic_poly.h"
void padic_poly_neg(padic_poly_t f, const padic_poly_t g,
const padic_ctx_t ctx)
{
const slong len = g->length;
if (len == 0 || g->val >= padic_poly_prec(f))
{
padic_poly_zero(f);
}
else
{
fmpz_t pow;
int alloc;
padic_poly_fit_length(f, len);
_padic_poly_set_length(f, len);
f->val = g->val;
alloc = _padic_ctx_pow_ui(pow, padic_poly_prec(f) - f->val, ctx);
if (padic_poly_prec(f) >= padic_poly_prec(g)) /* No reduction */
{
_fmpz_mod_poly_neg(f->coeffs, g->coeffs, len, pow);
}
else /* Reduction necessary? */
{
_fmpz_vec_scalar_mod_fmpz(f->coeffs, g->coeffs, len, pow);
_fmpz_mod_poly_neg(f->coeffs, f->coeffs, len, pow);
_padic_poly_normalise(f);
}
if (alloc)
fmpz_clear(pow);
}
}