66 lines
2.0 KiB
C
66 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) 2010 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 "fmpq_poly.h"
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void fmpq_poly_inv(fmpq_poly_t poly1, const fmpq_poly_t poly2)
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{
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if (poly2->length != 1)
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{
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flint_printf("Exception (fmpq_poly_inv). poly2 is not invertible.\n");
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abort();
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}
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if (poly1 == poly2)
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{
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fmpz_swap(poly1->coeffs, poly1->den);
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if (fmpz_sgn(poly1->den) < 0)
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{
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fmpz_neg(poly1->coeffs, poly1->coeffs);
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fmpz_neg(poly1->den, poly1->den);
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}
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}
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else
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{
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fmpq_poly_fit_length(poly1, 1);
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if (fmpz_sgn(poly2->coeffs) > 0)
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{
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fmpz_set(poly1->coeffs, poly2->den);
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fmpz_set(poly1->den, poly2->coeffs);
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}
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else
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{
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fmpz_neg(poly1->coeffs, poly2->den);
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fmpz_neg(poly1->den, poly2->coeffs);
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}
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_fmpq_poly_set_length(poly1, 1);
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}
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}
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