pqc/external/flint-2.4.3/arith/moebius_mu.c
2014-05-24 23:16:06 +02:00

57 lines
1.6 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) 2010 Fredrik Johansson
******************************************************************************/
#include "fmpz.h"
#include "arith.h"
int arith_moebius_mu(const fmpz_t n)
{
fmpz_factor_t factors;
slong i;
int mu;
if (fmpz_abs_fits_ui(n))
return n_moebius_mu(fmpz_get_ui(n));
fmpz_factor_init(factors);
fmpz_factor(factors, n);
mu = 1;
for (i = 0; i < factors->num; i++)
{
if (factors->exp[i] != UWORD(1))
{
mu = 0;
break;
}
}
if (factors->num % 2)
mu = -mu;
fmpz_factor_clear(factors);
return mu;
}