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/*=============================================================================
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) 2011 William Hart
Copyright (C) 2013 Martin Lee
******************************************************************************/
#undef ulong
#define ulong ulongxx/* interferes with system includes */
#include <stdlib.h>
#undef ulong
#include <gmp.h>
#define ulong mp_limb_t
#include "flint.h"
#include "nmod_vec.h"
#include "nmod_poly.h"
#include "ulong_extras.h"
void _nmod_poly_divrem_newton_n_preinv (mp_ptr Q, mp_ptr R, mp_srcptr A,
slong lenA, mp_srcptr B, slong lenB,
mp_srcptr Binv, slong lenBinv, nmod_t mod)
{
const slong lenQ = lenA - lenB + 1;
if (lenA == lenB + 1)
{
_nmod_poly_divrem_q1 (Q, R, A, lenA, B, lenB, mod);
return;
}
_nmod_poly_div_newton_n_preinv (Q, A, lenA, B, lenB, Binv, lenBinv, mod);
if (lenB > 1)
{
if (lenQ >= lenB - 1)
_nmod_poly_mullow(R, Q, lenQ, B, lenB - 1, lenB - 1, mod);
else
_nmod_poly_mullow(R, B, lenB - 1, Q, lenQ, lenB - 1, mod);
_nmod_vec_sub(R, A, R, lenB - 1, mod);
}
}
void nmod_poly_divrem_newton_n_preinv(nmod_poly_t Q, nmod_poly_t R,
const nmod_poly_t A, const nmod_poly_t B,
const nmod_poly_t Binv)
{
const slong lenA = A->length, lenB = B->length, lenBinv = Binv->length;
mp_ptr q, r;
if (lenB == 0)
{
flint_printf("Exception (nmod_poly_divrem_newton_n_preinv). Division by zero.\n");
abort();
}
if (lenA < lenB)
{
nmod_poly_set(R, A);
nmod_poly_zero(Q);
return;
}
if (lenA > 2 * lenB - 2)
{
flint_printf ("Exception (nmod_poly_divrem_newton_n_preinv).\n");
}
if (Q == A || Q == B || Q == Binv)
{
q = _nmod_vec_init(lenA - lenB + 1);
}
else
{
nmod_poly_fit_length(Q, lenA - lenB + 1);
q = Q->coeffs;
}
if (R == A || R == B || R == Binv)
{
r = _nmod_vec_init(lenB - 1);
}
else
{
nmod_poly_fit_length(R, lenB - 1);
r = R->coeffs;
}
_nmod_poly_divrem_newton_n_preinv (q, r, A->coeffs, lenA,
B->coeffs, lenB, Binv->coeffs,
lenBinv, B->mod);
if (Q == A || Q == B || Q == Binv)
{
_nmod_vec_clear(Q->coeffs);
Q->coeffs = q;
Q->alloc = lenA - lenB + 1;
}
if (R == A || R == B || R == Binv)
{
_nmod_vec_clear(R->coeffs);
R->coeffs = r;
R->alloc = lenB - 1;
}
Q->length = lenA - lenB + 1;
R->length = lenB - 1;
_nmod_poly_normalise(R);
}
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