75 lines
2.2 KiB
C
75 lines
2.2 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 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 "ulong_extras.h"
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#include "fmpz.h"
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void fmpz_gcdinv(fmpz_t d, fmpz_t a, const fmpz_t f, const fmpz_t g)
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{
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if (fmpz_is_zero(f))
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{
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fmpz_set(d, g);
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return;
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}
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if (!COEFF_IS_MPZ(*g)) /* g is small, hence f is small */
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{
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if (COEFF_IS_MPZ(*d))
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_fmpz_demote_val(d);
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if (COEFF_IS_MPZ(*a))
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_fmpz_demote_val(a);
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*d = n_gcdinv((mp_limb_t *) a, *f, *g);
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}
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else /* g is large */
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{
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_fmpz_promote_val(d);
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_fmpz_promote_val(a);
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if (!COEFF_IS_MPZ(*f)) /* f is small */
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{
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mpz_t fptr;
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fptr->_mp_alloc = 1;
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fptr->_mp_size = 1;
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fptr->_mp_d = (mp_limb_t *) f;
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mpz_gcdext(COEFF_TO_PTR(*d), COEFF_TO_PTR(*a), NULL,
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fptr, COEFF_TO_PTR(*g));
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}
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else /* f is large */
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{
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mpz_gcdext(COEFF_TO_PTR(*d), COEFF_TO_PTR(*a), NULL,
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COEFF_TO_PTR(*f), COEFF_TO_PTR(*g));
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}
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_fmpz_demote_val(d);
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_fmpz_demote_val(a);
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}
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}
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