101 lines
2.7 KiB
C
101 lines
2.7 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) 2011 William Hart
|
|
Copyright (C) 2011 Sebastian Pancratz
|
|
|
|
******************************************************************************/
|
|
|
|
#include <stdlib.h>
|
|
#include <gmp.h>
|
|
#include "flint.h"
|
|
#include "nmod_vec.h"
|
|
#include "nmod_poly.h"
|
|
#include "ulong_extras.h"
|
|
|
|
void _nmod_poly_div_newton(mp_ptr Q, mp_srcptr A, slong lenA,
|
|
mp_srcptr B, slong lenB, nmod_t mod)
|
|
{
|
|
const slong lenQ = lenA - lenB + 1;
|
|
mp_ptr Arev, Brev;
|
|
|
|
Arev = _nmod_vec_init(2 * lenQ);
|
|
Brev = Arev + lenQ;
|
|
|
|
_nmod_poly_reverse(Arev, A + (lenA - lenQ), lenQ, lenQ);
|
|
|
|
if (lenB >= lenQ)
|
|
{
|
|
_nmod_poly_reverse(Brev, B + (lenB - lenQ), lenQ, lenQ);
|
|
}
|
|
else
|
|
{
|
|
_nmod_poly_reverse(Brev, B, lenB, lenB);
|
|
flint_mpn_zero(Brev + lenB, lenQ - lenB);
|
|
}
|
|
|
|
_nmod_poly_div_series(Q, Arev, Brev, lenQ, mod);
|
|
|
|
_nmod_poly_reverse(Q, Q, lenQ, lenQ);
|
|
|
|
_nmod_vec_clear(Arev);
|
|
}
|
|
|
|
void nmod_poly_div_newton(nmod_poly_t Q, const nmod_poly_t A,
|
|
const nmod_poly_t B)
|
|
{
|
|
const slong lenA = A->length, lenB = B->length, lenQ = lenA - lenB + 1;
|
|
|
|
mp_ptr q;
|
|
|
|
if (lenB == 0)
|
|
{
|
|
flint_printf("Exception (nmod_poly_div_newton). Division by zero.\n");
|
|
abort();
|
|
}
|
|
|
|
if (lenA < lenB)
|
|
{
|
|
nmod_poly_zero(Q);
|
|
return;
|
|
}
|
|
|
|
if (Q == A || Q == B)
|
|
{
|
|
q = flint_malloc(lenQ * sizeof(mp_limb_t));
|
|
}
|
|
else
|
|
{
|
|
nmod_poly_fit_length(Q, lenQ);
|
|
q = Q->coeffs;
|
|
}
|
|
|
|
_nmod_poly_div_newton(q, A->coeffs, lenA, B->coeffs, lenB, B->mod);
|
|
|
|
if (Q == A || Q == B)
|
|
{
|
|
flint_free(Q->coeffs);
|
|
Q->coeffs = q;
|
|
Q->alloc = lenQ;
|
|
}
|
|
Q->length = lenQ;
|
|
}
|