69 lines
2.0 KiB
C
69 lines
2.0 KiB
C
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/*=============================================================================
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This file is part of FLINT.
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FLINT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FLINT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FLINT; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2011 Fredrik Johansson
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Copyright (C) 2012 Lina Kulakova
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******************************************************************************/
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#include "fmpz_mod_poly.h"
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#include "fmpz_vec.h"
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#include "ulong_extras.h"
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#include <string.h>
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int
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_fmpz_mod_poly_is_squarefree(const fmpz * f, slong len, const fmpz_t p)
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{
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fmpz * fd, * g;
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fmpz_t invd;
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slong dlen;
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int res;
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if (len <= 2)
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return len != 0;
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fd = _fmpz_vec_init(2 * (len - 1));
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g = fd + len - 1;
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_fmpz_mod_poly_derivative(fd, f, len, p);
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dlen = len - 1;
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FMPZ_VEC_NORM(fd, dlen);
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if (dlen)
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{
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fmpz_init(invd);
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fmpz_invmod(invd, fd + dlen - 1, p);
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res = (_fmpz_mod_poly_gcd(g, f, len, fd, dlen, invd, p) == 1);
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fmpz_clear(invd);
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}
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else
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res = 0; /* gcd(f, 0) = f, and len(f) > 2 */
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_fmpz_vec_clear(fd, 2 * (len - 1));
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return res;
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}
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int fmpz_mod_poly_is_squarefree(const fmpz_mod_poly_t f)
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{
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return _fmpz_mod_poly_is_squarefree(f->coeffs, f->length, &f->p);
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}
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