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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) 2010 Sebastian Pancratz
Copyright (C) 2011 William Hart
******************************************************************************/
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "nmod_vec.h"
#include "nmod_poly.h"
#include "mpn_extras.h"
void
_nmod_poly_divrem(mp_ptr Q, mp_ptr R, mp_srcptr A, slong lenA,
mp_srcptr B, slong lenB, nmod_t mod)
{
TMP_INIT;
if (lenA == lenB)
_nmod_poly_divrem_q0(Q, R, A, B, lenB, mod);
else if (lenA == lenB + 1)
_nmod_poly_divrem_q1(Q, R, A, lenA, B, lenB, mod);
else if (lenB < 15)
{
mp_ptr W;
TMP_START;
W = TMP_ALLOC(NMOD_DIVREM_BC_ITCH(lenA, lenB, mod)*sizeof(mp_limb_t));
_nmod_poly_divrem_basecase(Q, R, W, A, lenA, B, lenB, mod);
TMP_END;
}
else if (lenB < 6000)
_nmod_poly_divrem_divconquer(Q, R, A, lenA, B, lenB, mod);
else
_nmod_poly_divrem_newton(Q, R, A, lenA, B, lenB, mod);
}
void nmod_poly_divrem(nmod_poly_t Q, nmod_poly_t R,
const nmod_poly_t A, const nmod_poly_t B)
{
const slong lenA = A->length, lenB = B->length;
nmod_poly_t tQ, tR;
mp_ptr q, r;
if (lenB == 0)
{
flint_printf("Exception (nmod_poly_divrem). Division by zero.");
abort();
}
if (lenA < lenB)
{
nmod_poly_set(R, A);
nmod_poly_zero(Q);
return;
}
if (Q == A || Q == B)
{
nmod_poly_init2_preinv(tQ, A->mod.n, A->mod.ninv, lenA - lenB + 1);
q = tQ->coeffs;
}
else
{
nmod_poly_fit_length(Q, lenA - lenB + 1);
q = Q->coeffs;
}
if (R == A || R == B)
{
nmod_poly_init2_preinv(tR, B->mod.n, B->mod.ninv, lenB - 1);
r = tR->coeffs;
}
else
{
nmod_poly_fit_length(R, lenB - 1);
r = R->coeffs;
}
_nmod_poly_divrem(q, r, A->coeffs, lenA, B->coeffs, lenB, A->mod);
if (Q == A || Q == B)
{
nmod_poly_swap(Q, tQ);
nmod_poly_clear(tQ);
}
if (R == A || R == B)
{
nmod_poly_swap(R, tR);
nmod_poly_clear(tR);
}
Q->length = lenA - lenB + 1;
R->length = lenB - 1;
_nmod_poly_normalise(R);
}
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