133 lines
4.2 KiB
C
133 lines
4.2 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, 2011 Sebastian Pancratz
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******************************************************************************/
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#include "fmpq_poly.h"
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#include "fmpz_poly_q.h"
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void fmpz_poly_q_mul(fmpz_poly_q_t rop,
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const fmpz_poly_q_t op1, const fmpz_poly_q_t op2)
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{
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if (fmpz_poly_q_is_zero(op1) || fmpz_poly_q_is_zero(op2))
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{
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fmpz_poly_q_zero(rop);
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return;
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}
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if (op1 == op2)
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{
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fmpz_poly_pow(rop->num, op1->num, 2);
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fmpz_poly_pow(rop->den, op1->den, 2);
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return;
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}
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if (rop == op1 || rop == op2)
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{
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fmpz_poly_q_t t;
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fmpz_poly_q_init(t);
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fmpz_poly_q_mul(t, op1, op2);
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fmpz_poly_q_swap(rop, t);
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fmpz_poly_q_clear(t);
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return;
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}
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/*
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From here on, we may assume that rop, op1 and op2 refer to distinct
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objects in memory, and that op1 and op2 are non-zero
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*/
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/* Polynomials? */
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if (fmpz_poly_length(op1->den) == 1 && fmpz_poly_length(op2->den) == 1)
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{
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const slong len1 = fmpz_poly_length(op1->num);
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const slong len2 = fmpz_poly_length(op2->num);
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fmpz_poly_fit_length(rop->num, len1 + len2 - 1);
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if (len1 >= len2)
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{
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_fmpq_poly_mul(rop->num->coeffs, rop->den->coeffs,
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op1->num->coeffs, op1->den->coeffs, len1,
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op2->num->coeffs, op2->den->coeffs, len2);
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}
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else
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{
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_fmpq_poly_mul(rop->num->coeffs, rop->den->coeffs,
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op2->num->coeffs, op2->den->coeffs, len2,
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op1->num->coeffs, op1->den->coeffs, len1);
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}
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_fmpz_poly_set_length(rop->num, len1 + len2 - 1);
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_fmpz_poly_set_length(rop->den, 1);
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return;
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}
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fmpz_poly_gcd(rop->num, op1->num, op2->den);
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if (fmpz_poly_is_one(rop->num))
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{
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fmpz_poly_gcd(rop->den, op2->num, op1->den);
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if (fmpz_poly_is_one(rop->den))
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{
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fmpz_poly_mul(rop->num, op1->num, op2->num);
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fmpz_poly_mul(rop->den, op1->den, op2->den);
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}
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else
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{
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fmpz_poly_div(rop->num, op2->num, rop->den);
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fmpz_poly_mul(rop->num, op1->num, rop->num);
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fmpz_poly_div(rop->den, op1->den, rop->den);
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fmpz_poly_mul(rop->den, rop->den, op2->den);
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}
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}
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else
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{
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fmpz_poly_gcd(rop->den, op2->num, op1->den);
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if (fmpz_poly_is_one(rop->den))
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{
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fmpz_poly_div(rop->den, op2->den, rop->num);
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fmpz_poly_mul(rop->den, op1->den, rop->den);
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fmpz_poly_div(rop->num, op1->num, rop->num);
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fmpz_poly_mul(rop->num, rop->num, op2->num);
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}
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else
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{
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fmpz_poly_t t, u;
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fmpz_poly_init(t);
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fmpz_poly_init(u);
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fmpz_poly_div(t, op1->num, rop->num);
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fmpz_poly_div(u, op2->den, rop->num);
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fmpz_poly_div(rop->num, op2->num, rop->den);
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fmpz_poly_mul(rop->num, t, rop->num);
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fmpz_poly_div(rop->den, op1->den, rop->den);
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fmpz_poly_mul(rop->den, rop->den, u);
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fmpz_poly_clear(t);
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fmpz_poly_clear(u);
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}
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}
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}
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