pqc/external/flint-2.4.3/fmpz_poly_q/add.c
2014-05-24 23:16:06 +02:00

256 lines
7.4 KiB
C

/*=============================================================================
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_add_in_place(fmpz_poly_q_t rop, const fmpz_poly_q_t op)
{
fmpz_poly_t d, poly, r2, s2;
if (rop == op)
{
fmpz_poly_q_scalar_mul_si(rop, rop, 2);
return;
}
if (fmpz_poly_q_is_zero(rop))
{
fmpz_poly_q_set(rop, op);
return;
}
if (fmpz_poly_q_is_zero(op))
{
return;
}
/* Polynomials? */
if (fmpz_poly_length(rop->den) == 1 && fmpz_poly_length(op->den) == 1)
{
const slong len1 = fmpz_poly_length(rop->num);
const slong len2 = fmpz_poly_length(op->num);
fmpz_poly_fit_length(rop->num, FLINT_MAX(len1, len2));
_fmpq_poly_add(rop->num->coeffs, rop->den->coeffs,
rop->num->coeffs, rop->den->coeffs, len1,
op->num->coeffs, op->den->coeffs, len2);
_fmpz_poly_set_length(rop->num, FLINT_MAX(len1, len2));
_fmpz_poly_set_length(rop->den, 1);
_fmpz_poly_normalise(rop->num);
return;
}
/* Denominators equal to one? */
if (fmpz_poly_is_one(rop->den))
{
fmpz_poly_mul(rop->num, rop->num, op->den);
fmpz_poly_add(rop->num, rop->num, op->num);
fmpz_poly_set(rop->den, op->den);
return;
}
if (fmpz_poly_is_one(op->den))
{
fmpz_poly_init(poly);
fmpz_poly_mul(poly, rop->den, op->num);
fmpz_poly_add(rop->num, rop->num, poly);
fmpz_poly_clear(poly);
return;
}
/* Henrici's algorithm for summation in quotient fields */
fmpz_poly_init(d);
fmpz_poly_gcd(d, rop->den, op->den);
if (fmpz_poly_is_one(d))
{
fmpz_poly_mul(rop->num, rop->num, op->den);
fmpz_poly_mul(d, rop->den, op->num); /* Using d as temp */
fmpz_poly_add(rop->num, rop->num, d);
fmpz_poly_mul(rop->den, rop->den, op->den);
}
else
{
fmpz_poly_init(r2);
fmpz_poly_init(s2);
fmpz_poly_div(r2, rop->den, d);
fmpz_poly_div(s2, op->den, d);
fmpz_poly_mul(rop->num, rop->num, s2);
fmpz_poly_mul(s2, op->num, r2); /* Using s2 as temp */
fmpz_poly_add(rop->num, rop->num, s2);
if (fmpz_poly_is_zero(rop->num))
{
fmpz_poly_zero(rop->den);
fmpz_poly_set_coeff_si(rop->den, 0, 1);
}
else
{
fmpz_poly_mul(rop->den, r2, op->den);
fmpz_poly_gcd(r2, rop->num, d); /* Using r2 as temp */
if (!fmpz_poly_is_one(r2))
{
fmpz_poly_div(rop->num, rop->num, r2);
fmpz_poly_div(rop->den, rop->den, r2);
}
}
fmpz_poly_clear(r2);
fmpz_poly_clear(s2);
}
fmpz_poly_clear(d);
}
void
fmpz_poly_q_add(fmpz_poly_q_t rop,
const fmpz_poly_q_t op1, const fmpz_poly_q_t op2)
{
fmpz_poly_t d, r2, s2;
if (fmpz_poly_q_is_zero(op1))
{
fmpz_poly_q_set(rop, op2);
return;
}
if (fmpz_poly_q_is_zero(op2))
{
fmpz_poly_q_set(rop, op1);
return;
}
if (op1 == op2)
{
fmpz_poly_q_scalar_mul_si(rop, op1, 2);
return;
}
if (rop == op1)
{
fmpz_poly_q_add_in_place(rop, op2);
return;
}
if (rop == op2)
{
fmpz_poly_q_add_in_place(rop, op1);
return;
}
/*
From here on, we may assume that rop, op1 and op2 all refer to
distinct objects in memory, although they may still be equal
*/
/* 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, FLINT_MAX(len1, len2));
_fmpq_poly_add(rop->num->coeffs, rop->den->coeffs,
op1->num->coeffs, op1->den->coeffs, len1,
op2->num->coeffs, op2->den->coeffs, len2);
_fmpz_poly_set_length(rop->num, FLINT_MAX(len1, len2));
_fmpz_poly_set_length(rop->den, 1);
_fmpz_poly_normalise(rop->num);
return;
}
/* Denominators equal to one? */
if (fmpz_poly_is_one(op1->den))
{
fmpz_poly_mul(rop->num, op1->num, op2->den);
fmpz_poly_add(rop->num, rop->num, op2->num);
fmpz_poly_set(rop->den, op2->den);
return;
}
if (fmpz_poly_is_one(op2->den))
{
fmpz_poly_mul(rop->num, op2->num, op1->den);
fmpz_poly_add(rop->num, op1->num, rop->num);
fmpz_poly_set(rop->den, op1->den);
return;
}
/* Henrici's algorithm for summation in quotient fields */
/*
We begin by using rop->num as a temporary variable for
the gcd of the two denominators' greatest common divisor
*/
fmpz_poly_gcd(rop->num, op1->den, op2->den);
if (fmpz_poly_is_one(rop->num))
{
fmpz_poly_mul(rop->num, op1->num, op2->den);
fmpz_poly_mul(rop->den, op1->den, op2->num); /* Using rop->den as temp */
fmpz_poly_add(rop->num, rop->num, rop->den);
fmpz_poly_mul(rop->den, op1->den, op2->den);
}
else
{
/*
We now copy rop->num into a new variable d, so we
no longer need rop->num as a temporary variable
*/
fmpz_poly_init(d);
fmpz_poly_swap(d, rop->num);
fmpz_poly_init(r2);
fmpz_poly_init(s2);
fmpz_poly_div(r2, op1->den, d); /* +ve leading coeff */
fmpz_poly_div(s2, op2->den, d); /* +ve leading coeff */
fmpz_poly_mul(rop->num, op1->num, s2);
fmpz_poly_mul(rop->den, op2->num, r2); /* Using rop->den as temp */
fmpz_poly_add(rop->num, rop->num, rop->den);
if (fmpz_poly_is_zero(rop->num))
{
fmpz_poly_zero(rop->den);
fmpz_poly_set_coeff_si(rop->den, 0, 1);
}
else
{
fmpz_poly_mul(rop->den, op1->den, s2);
fmpz_poly_gcd(r2, rop->num, d);
if (!fmpz_poly_is_one(r2))
{
fmpz_poly_div(rop->num, rop->num, r2);
fmpz_poly_div(rop->den, rop->den, r2);
}
}
fmpz_poly_clear(d);
fmpz_poly_clear(r2);
fmpz_poly_clear(s2);
}
}