pqc/external/flint-2.4.3/fmpz_poly_q/mul.c

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2014-05-18 22:03:37 +00:00
/*=============================================================================
This file is part of FLINT.
FLINT is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
FLINT is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with FLINT; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2010, 2011 Sebastian Pancratz
******************************************************************************/
#include "fmpq_poly.h"
#include "fmpz_poly_q.h"
void fmpz_poly_q_mul(fmpz_poly_q_t rop,
const fmpz_poly_q_t op1, const fmpz_poly_q_t op2)
{
if (fmpz_poly_q_is_zero(op1) || fmpz_poly_q_is_zero(op2))
{
fmpz_poly_q_zero(rop);
return;
}
if (op1 == op2)
{
fmpz_poly_pow(rop->num, op1->num, 2);
fmpz_poly_pow(rop->den, op1->den, 2);
return;
}
if (rop == op1 || rop == op2)
{
fmpz_poly_q_t t;
fmpz_poly_q_init(t);
fmpz_poly_q_mul(t, op1, op2);
fmpz_poly_q_swap(rop, t);
fmpz_poly_q_clear(t);
return;
}
/*
From here on, we may assume that rop, op1 and op2 refer to distinct
objects in memory, and that op1 and op2 are non-zero
*/
/* Polynomials? */
if (fmpz_poly_length(op1->den) == 1 && fmpz_poly_length(op2->den) == 1)
{
const slong len1 = fmpz_poly_length(op1->num);
const slong len2 = fmpz_poly_length(op2->num);
fmpz_poly_fit_length(rop->num, len1 + len2 - 1);
if (len1 >= len2)
{
_fmpq_poly_mul(rop->num->coeffs, rop->den->coeffs,
op1->num->coeffs, op1->den->coeffs, len1,
op2->num->coeffs, op2->den->coeffs, len2);
}
else
{
_fmpq_poly_mul(rop->num->coeffs, rop->den->coeffs,
op2->num->coeffs, op2->den->coeffs, len2,
op1->num->coeffs, op1->den->coeffs, len1);
}
_fmpz_poly_set_length(rop->num, len1 + len2 - 1);
_fmpz_poly_set_length(rop->den, 1);
return;
}
fmpz_poly_gcd(rop->num, op1->num, op2->den);
if (fmpz_poly_is_one(rop->num))
{
fmpz_poly_gcd(rop->den, op2->num, op1->den);
if (fmpz_poly_is_one(rop->den))
{
fmpz_poly_mul(rop->num, op1->num, op2->num);
fmpz_poly_mul(rop->den, op1->den, op2->den);
}
else
{
fmpz_poly_div(rop->num, op2->num, rop->den);
fmpz_poly_mul(rop->num, op1->num, rop->num);
fmpz_poly_div(rop->den, op1->den, rop->den);
fmpz_poly_mul(rop->den, rop->den, op2->den);
}
}
else
{
fmpz_poly_gcd(rop->den, op2->num, op1->den);
if (fmpz_poly_is_one(rop->den))
{
fmpz_poly_div(rop->den, op2->den, rop->num);
fmpz_poly_mul(rop->den, op1->den, rop->den);
fmpz_poly_div(rop->num, op1->num, rop->num);
fmpz_poly_mul(rop->num, rop->num, op2->num);
}
else
{
fmpz_poly_t t, u;
fmpz_poly_init(t);
fmpz_poly_init(u);
fmpz_poly_div(t, op1->num, rop->num);
fmpz_poly_div(u, op2->den, rop->num);
fmpz_poly_div(rop->num, op2->num, rop->den);
fmpz_poly_mul(rop->num, t, rop->num);
fmpz_poly_div(rop->den, op1->den, rop->den);
fmpz_poly_mul(rop->den, rop->den, u);
fmpz_poly_clear(t);
fmpz_poly_clear(u);
}
}
}