1 /*
2 Copyright (C) 2016 Fredrik Johansson
3
4 This file is part of Arb.
5
6 Arb is free software: you can redistribute it and/or modify it under
7 the terms of the GNU Lesser General Public License (LGPL) as published
8 by the Free Software Foundation; either version 2.1 of the License, or
9 (at your option) any later version. See <http://www.gnu.org/licenses/>.
10 */
11
12 #include "acb.h"
13
14 void
acb_sgn(acb_t res,const acb_t z,slong prec)15 acb_sgn(acb_t res, const acb_t z, slong prec)
16 {
17 if (arb_is_zero(acb_imagref(z)))
18 {
19 arb_sgn(acb_realref(res), acb_realref(z));
20 arb_zero(acb_imagref(res));
21 }
22 else if (arb_is_zero(acb_realref(z)))
23 {
24 arb_sgn(acb_imagref(res), acb_imagref(z));
25 arb_zero(acb_realref(res));
26 }
27 else
28 {
29 arb_t t;
30 arb_init(t);
31 acb_abs(t, z, prec);
32 arb_inv(t, t, prec);
33
34 if (arb_is_finite(t))
35 {
36 acb_mul_arb(res, z, t, prec);
37 }
38 else
39 {
40 arf_zero(arb_midref(acb_realref(res)));
41 mag_one(arb_radref(acb_realref(res)));
42 arb_set(acb_imagref(res), acb_realref(res));
43 }
44
45 arb_clear(t);
46 }
47 }
48
49