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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 Sebastian Pancratz
******************************************************************************/
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "ulong_extras.h"
slong _fmpz_remove(fmpz_t x, const fmpz_t f, double finv)
{
fmpz y = *x;
fmpz q = *f;
if (!COEFF_IS_MPZ(y)) /* x is small */
{
if (!COEFF_IS_MPZ(q)) /* f is small */
{
if (y > 0)
{
return n_remove2_precomp((mp_limb_t *) x, q, finv);
}
else
{
ulong z = - (ulong) y;
slong e = n_remove2_precomp(&z, q, finv);
if (e > 0)
{
*x = - (slong) z;
}
return e;
}
}
else /* f is large */
{
return 0;
}
}
else /* x is large */
{
__mpz_struct *z = COEFF_TO_PTR(y);
if (!COEFF_IS_MPZ(q)) /* f is small */
{
if (!flint_mpz_divisible_ui_p(z, q))
{
return 0;
}
else
{
flint_mpz_divexact_ui(z, z, q);
if (!flint_mpz_divisible_ui_p(z, q))
{
_fmpz_demote_val(x);
return 1;
}
else
{
mpz_t r;
slong e;
flint_mpz_divexact_ui(z, z, q);
flint_mpz_init_set_ui(r, q);
e = 2 + mpz_remove(z, z, r);
mpz_clear(r);
_fmpz_demote_val(x);
return e;
}
}
}
else /* f is large */
{
__mpz_struct *r = COEFF_TO_PTR(q);
if (!mpz_divisible_p(z, r))
{
return 0;
}
else
{
slong e;
mpz_divexact(z, z, r);
e = 1 + mpz_remove(z, z, r);
_fmpz_demote_val(x);
return e;
}
}
}
}
slong fmpz_remove(fmpz_t rop, const fmpz_t op, const fmpz_t f)
{
double finv;
if ((fmpz_sgn(f) <= 0) || fmpz_is_one(f))
{
flint_printf("Exception (fmpz_remove). factor f <= 1.\n");
abort();
}
if (rop == f)
{
slong ans;
fmpz_t t;
fmpz_init(t);
ans = fmpz_remove(t, op, f);
fmpz_swap(rop, t);
fmpz_clear(t);
return ans;
}
finv = (!COEFF_IS_MPZ((*f))) ? n_precompute_inverse(*f) : 0;
fmpz_set(rop, op);
return _fmpz_remove(rop, f, finv);
}
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