74 lines
2.1 KiB
C
74 lines
2.1 KiB
C
/*=============================================================================
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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) 2010 Sebastian Pancratz
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******************************************************************************/
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#include <gmp.h>
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#include "flint.h"
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#include "fmpz.h"
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#include "fmpz_vec.h"
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#include "fmpz_poly.h"
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#include "fmpq_poly.h"
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int _fmpz_poly_is_squarefree(const fmpz * poly, slong len)
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{
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if (len < 3)
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{
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return 1;
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}
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else if (len == 3)
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{
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int ans;
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fmpz_t lhs, rhs;
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fmpz_init(lhs);
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fmpz_init(rhs);
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fmpz_mul(lhs, poly + 1, poly + 1);
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fmpz_mul(rhs, poly, poly + 2);
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fmpz_mul_ui(rhs, rhs, 4);
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ans = !fmpz_equal(lhs, rhs);
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fmpz_clear(lhs);
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fmpz_clear(rhs);
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return ans;
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}
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else
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{
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int ans;
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fmpz * w = _fmpz_vec_init(2 * len);
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_fmpz_poly_derivative(w, poly, len);
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_fmpz_poly_gcd(w + len, poly, len, w, len - WORD(1));
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ans = _fmpz_vec_is_zero(w + len + 1, len - 2);
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_fmpz_vec_clear(w, 2 * len);
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return ans;
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}
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}
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int fmpz_poly_is_squarefree(const fmpz_poly_t poly)
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{
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return _fmpz_poly_is_squarefree(poly->coeffs, poly->length);
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}
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