117 lines
3.6 KiB
C
117 lines
3.6 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_compose(fmpz * res, fmpz_t den, const fmpz * poly1, const fmpz_t den1,
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slong len1, const fmpz * poly2, const fmpz_t den2, slong len2)
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{
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if (*den2 == WORD(1))
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{
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_fmpz_poly_compose(res, poly1, len1, poly2, len2);
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fmpz_set(den, den1);
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_fmpq_poly_canonicalise(res, den, (len1 - WORD(1)) * (len2 - WORD(1)) + WORD(1));
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}
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else
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{
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fmpz_t one;
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fmpz * v = _fmpz_vec_init(len1);
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fmpz_init(one);
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fmpz_one(one);
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_fmpq_poly_rescale(v, den, poly1, den1, len1, one, den2);
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_fmpz_poly_compose(res, v, len1, poly2, len2);
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_fmpq_poly_canonicalise(res, den, (len1 - WORD(1)) * (len2 - WORD(1)) + WORD(1));
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fmpz_clear(one);
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_fmpz_vec_clear(v, len1);
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}
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}
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void
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fmpq_poly_compose(fmpq_poly_t res,
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const fmpq_poly_t poly1, const fmpq_poly_t poly2)
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{
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const slong len1 = poly1->length;
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const slong len2 = poly2->length;
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slong lenr;
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if (len1 == WORD(0))
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{
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fmpq_poly_zero(res);
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return;
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}
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if (len1 == WORD(1) || len2 == WORD(0))
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{
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fmpq_poly_fit_length(res, 1);
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fmpz_set(res->coeffs, poly1->coeffs);
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fmpz_set(res->den, poly1->den);
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{
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fmpz_t d;
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fmpz_init(d);
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fmpz_gcd(d, res->coeffs, res->den);
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if (*d != WORD(1))
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{
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fmpz_divexact(res->coeffs, res->coeffs, d);
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fmpz_divexact(res->den, res->den, d);
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}
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fmpz_clear(d);
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}
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_fmpq_poly_set_length(res, 1);
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_fmpq_poly_normalise(res);
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return;
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}
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lenr = (len1 - WORD(1)) * (len2 - WORD(1)) + WORD(1);
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if ((res != poly1) && (res != poly2))
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{
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fmpq_poly_fit_length(res, lenr);
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_fmpq_poly_compose(res->coeffs, res->den,
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poly1->coeffs, poly1->den, len1,
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poly2->coeffs, poly2->den, len2);
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_fmpq_poly_set_length(res, lenr);
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_fmpq_poly_normalise(res);
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}
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else
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{
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fmpq_poly_t t;
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fmpq_poly_init2(t, lenr);
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_fmpq_poly_compose(t->coeffs, t->den,
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poly1->coeffs, poly1->den, len1,
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poly2->coeffs, poly2->den, len2);
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_fmpq_poly_set_length(t, lenr);
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_fmpq_poly_normalise(t);
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fmpq_poly_swap(res, t);
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fmpq_poly_clear(t);
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}
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}
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