arb/acb/sgn.c
2016-04-26 17:20:05 +02:00

48 lines
1.1 KiB
C

/*
Copyright (C) 2016 Fredrik Johansson
This file is part of Arb.
Arb is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version. See <http://www.gnu.org/licenses/>.
*/
#include "acb.h"
void
acb_sgn(acb_t res, const acb_t z, slong prec)
{
if (arb_is_zero(acb_imagref(z)))
{
arb_sgn(acb_realref(res), acb_realref(z));
arb_zero(acb_imagref(res));
}
else if (arb_is_zero(acb_realref(z)))
{
arb_sgn(acb_imagref(res), acb_imagref(z));
arb_zero(acb_realref(res));
}
else
{
arb_t t;
arb_init(t);
acb_abs(t, z, prec);
arb_inv(t, t, prec);
if (arb_is_finite(t))
{
acb_mul_arb(res, z, t, prec);
}
else
{
arf_zero(arb_midref(acb_realref(res)));
mag_one(arb_radref(acb_realref(res)));
arb_set(acb_imagref(res), acb_realref(res));
}
arb_clear(t);
}
}