pqc/external/flint-2.4.3/fmpz_poly/mulhigh_n.c

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2014-05-18 22:03:37 +00:00
/*=============================================================================
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) 2008, 2009 William Hart
******************************************************************************/
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_vec.h"
#include "fmpz_poly.h"
void
fmpz_poly_mulhigh_n(fmpz_poly_t res,
const fmpz_poly_t poly1, const fmpz_poly_t poly2, slong n)
{
mp_size_t limbs1 = _fmpz_vec_max_limbs(poly1->coeffs, poly1->length);
mp_size_t limbs2 = _fmpz_vec_max_limbs(poly2->coeffs, poly2->length);
mp_size_t len1 = poly1->length;
mp_size_t len2 = poly2->length;
mp_size_t limbsx = FLINT_MAX(limbs1, limbs2);
if (n == 0)
{
fmpz_poly_zero(res);
return;
}
if (n < 4)
{
fmpz_poly_mulhigh_classical(res, poly1, poly2, n - 1);
return;
}
if ((limbsx > 4) && (n < 16))
fmpz_poly_mulhigh_karatsuba_n(res, poly1, poly2, n);
else if (limbs1 + limbs2 <= 8)
fmpz_poly_mul_KS(res, poly1, poly2);
else if ((limbs1+limbs2)/2048 > len1 + len2)
fmpz_poly_mul_KS(res, poly1, poly2);
else if ((limbs1 + limbs2)*FLINT_BITS*4 < len1 + len2)
fmpz_poly_mul_KS(res, poly1, poly2);
else
fmpz_poly_mul_SS(res, poly1, poly2);
}