pqc/external/flint-2.4.3/fmpz_vec/height_index.c

96 lines
2.7 KiB
C
Raw Normal View History

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) 2012 Fredrik Johansson
******************************************************************************/
#include <gmp.h>
#include "flint.h"
#include "fmpz.h"
#include "fmpz_vec.h"
slong
_fmpz_vec_height_index(const fmpz * vec, slong len)
{
if (len == 1)
{
return 0;
}
else
{
fmpz c;
mp_srcptr max_d;
slong max_mpz_limbs, i, max_i, max_coeff, mpz_limbs;
max_coeff = 0;
max_i = 0;
for (i = 0; i < len; i++)
{
c = vec[i];
if (!COEFF_IS_MPZ(c))
{
c = FLINT_ABS(c);
if (c > max_coeff)
{
max_coeff = c;
max_i = i;
}
}
else
{
__mpz_struct * mpz_ptr = COEFF_TO_PTR(c);
max_d = mpz_ptr->_mp_d;
max_mpz_limbs = mpz_ptr->_mp_size;
max_mpz_limbs = FLINT_ABS(max_mpz_limbs);
max_i = i;
i++;
break;
}
}
for ( ; i < len; i++)
{
c = vec[i];
/* we have found at least one mpz, so only look for those */
if (COEFF_IS_MPZ(c))
{
__mpz_struct * mpz_ptr = COEFF_TO_PTR(c);
mpz_limbs = mpz_ptr->_mp_size;
mpz_limbs = FLINT_ABS(mpz_limbs);
if (mpz_limbs > max_mpz_limbs ||
((mpz_limbs == max_mpz_limbs) &&
(mpn_cmp(mpz_ptr->_mp_d, max_d, max_mpz_limbs) > 0)))
{
max_d = mpz_ptr->_mp_d;
max_mpz_limbs = mpz_limbs;
max_i = i;
}
}
}
return max_i;
}
}