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/*
Copyright (C) 2011 Fredrik Johansson
Copyright (C) 2012 Lina Kulakova
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "fmpz_vec.h"
#include "fmpz_mod.h"
#include "fmpz_mod_poly.h"
#include "fmpz_mod_poly_factor.h"
int
_fmpz_mod_poly_is_squarefree(const fmpz * f, slong len, const fmpz_mod_ctx_t ctx)
{
fmpz * fd, * g;
slong dlen;
int res;
if (len <= 2)
return len != 0;
fd = _fmpz_vec_init(2 * (len - 1));
g = fd + len - 1;
_fmpz_mod_poly_derivative(fd, f, len, ctx);
dlen = len - 1;
FMPZ_VEC_NORM(fd, dlen);
if (dlen)
res = (_fmpz_mod_poly_gcd(g, f, len, fd, dlen, ctx) == 1);
else
res = 0; /* gcd(f, 0) = f, and len(f) > 2 */
_fmpz_vec_clear(fd, 2 * (len - 1));
return res;
}
int fmpz_mod_poly_is_squarefree(const fmpz_mod_poly_t f,
const fmpz_mod_ctx_t ctx)
{
return _fmpz_mod_poly_is_squarefree(f->coeffs, f->length, ctx);
}