93 lines
2.6 KiB
C
93 lines
2.6 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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void
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_fmpq_poly_rescale(fmpz * res, fmpz_t denr,
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const fmpz * poly, const fmpz_t den, slong len,
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const fmpz_t xnum, const fmpz_t xden)
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{
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if (len < WORD(2))
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{
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if (res != poly)
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{
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_fmpz_vec_set(res, poly, len);
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fmpz_set(denr, den);
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}
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}
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else
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{
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slong i;
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fmpz_t t;
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fmpz_init(t);
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fmpz_one(t);
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fmpz_set(res, poly);
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for (i = WORD(1); i < len; i++)
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{
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fmpz_mul(t, t, xnum);
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fmpz_mul(res + i, poly + i, t);
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}
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fmpz_one(t);
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for (i = len - WORD(2); i >= WORD(0); i--)
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{
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fmpz_mul(t, t, xden);
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fmpz_mul(res + i, res + i, t);
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}
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fmpz_mul(denr, den, t);
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fmpz_clear(t);
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_fmpq_poly_canonicalise(res, denr, len);
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}
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}
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void fmpq_poly_rescale(fmpq_poly_t res, const fmpq_poly_t poly, const fmpq_t x)
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{
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if (fmpq_is_zero(x))
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{
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fmpq_poly_zero(res);
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}
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else if (poly->length < WORD(2))
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{
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fmpq_poly_set(res, poly);
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}
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else
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{
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fmpq_poly_fit_length(res, poly->length);
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_fmpq_poly_rescale(res->coeffs, res->den,
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poly->coeffs, poly->den, poly->length,
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fmpq_numref(x), fmpq_denref(x));
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_fmpq_poly_set_length(res, poly->length);
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}
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}
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