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

67 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 <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_poly.h"
int
_fmpz_poly_sqrt(fmpz * res, const fmpz * poly, slong len)
{
return _fmpz_poly_sqrt_classical(res, poly, len);
}
int
fmpz_poly_sqrt(fmpz_poly_t b, const fmpz_poly_t a)
{
slong blen, len = a->length;
int result;
if (len % 2 == 0)
{
fmpz_poly_zero(b);
return len == 0;
}
if (b == a)
{
fmpz_poly_t tmp;
fmpz_poly_init(tmp);
result = fmpz_poly_sqrt(tmp, a);
fmpz_poly_swap(b, tmp);
fmpz_poly_clear(tmp);
return result;
}
blen = len / 2 + 1;
fmpz_poly_fit_length(b, blen);
_fmpz_poly_set_length(b, blen);
result = _fmpz_poly_sqrt(b->coeffs, a->coeffs, len);
if (!result)
_fmpz_poly_set_length(b, 0);
return result;
}