arb/acb/sgn.c
2016-02-18 00:55:43 +01:00

62 lines
1.8 KiB
C

/*=============================================================================
This file is part of ARB.
ARB 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.
ARB 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 ARB; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2016 Fredrik Johansson
******************************************************************************/
#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);
}
}