97 lines
2.7 KiB
C
97 lines
2.7 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 Andy Novocin
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Copyright (C) 2011 Sebastian Pancratz
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******************************************************************************/
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#include <stdlib.h>
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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_poly.h"
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void fmpz_poly_factor_squarefree(fmpz_poly_factor_t fac, const fmpz_poly_t F)
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{
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fmpz_poly_content(&(fac->c), F);
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if (fmpz_sgn(fmpz_poly_lead(F)) < 0)
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fmpz_neg(&(fac->c), &(fac->c));
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if (F->length > 1)
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{
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fmpz_poly_t f, d, t1;
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fmpz_poly_init(f);
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fmpz_poly_init(d);
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fmpz_poly_init(t1);
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fmpz_poly_scalar_divexact_fmpz(f, F, &(fac->c));
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fmpz_poly_derivative(t1, f);
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fmpz_poly_gcd(d, f, t1);
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if (d->length == 1)
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{
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fmpz_poly_factor_insert(fac, f, 1);
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}
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else
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{
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fmpz_poly_t v, w, s;
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slong i;
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fmpz_poly_init(v);
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fmpz_poly_init(w);
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fmpz_poly_init(s);
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fmpz_poly_div(v, f, d);
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fmpz_poly_div(w, t1, d);
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for (i = 1; ; i++)
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{
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fmpz_poly_derivative(t1, v);
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fmpz_poly_sub(s, w, t1);
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if (s->length == 0)
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{
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if (v->length > 1)
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fmpz_poly_factor_insert(fac, v, i);
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break;
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}
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fmpz_poly_gcd(d, v, s);
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fmpz_poly_div(v, v, d);
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fmpz_poly_div(w, s, d);
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if (d->length > 1)
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fmpz_poly_factor_insert(fac, d, i);
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}
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fmpz_poly_clear(v);
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fmpz_poly_clear(w);
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fmpz_poly_clear(s);
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}
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fmpz_poly_clear(f);
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fmpz_poly_clear(d);
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fmpz_poly_clear(t1);
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}
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}
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