pqc/external/flint-2.4.3/arith/dedekind_sum_coprime_d.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) 2011 Fredrik Johansson
******************************************************************************/
#include <math.h>
#include "arith.h"
double
arith_dedekind_sum_coprime_d(double h, double k)
{
double a, b, t, s, sign;
if (k <= 2)
return 0.0;
a = k;
b = h;
s = 0.0;
sign = 1.0;
while (b > 0)
{
s += sign * (1.0 + a*a + b*b) / (a * b);
t = fmod(a, b);
a = b;
b = t;
sign = -sign;
}
s *= (1./12);
if (sign < 0)
s -= 0.25;
return s;
}