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7799b7b3 UD |
1 | /* Compute projection of complex long double value to Riemann sphere. |
2 | Copyright (C) 1997 Free Software Foundation, Inc. | |
3 | This file is part of the GNU C Library. | |
4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. | |
5 | ||
6 | The GNU C Library is free software; you can redistribute it and/or | |
7 | modify it under the terms of the GNU Library General Public License as | |
8 | published by the Free Software Foundation; either version 2 of the | |
9 | License, or (at your option) any later version. | |
10 | ||
11 | The GNU C Library is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | Library General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU Library General Public | |
17 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
18 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
19 | Boston, MA 02111-1307, USA. */ | |
20 | ||
21 | #include <complex.h> | |
22 | #include <math.h> | |
23 | ||
24 | ||
25 | __complex__ long double | |
26 | __cprojl (__complex__ long double x) | |
27 | { | |
28 | __complex__ long double res; | |
29 | ||
779ae82e | 30 | if (!isfinite (__real__ x) || !isfinite (__imag__ x)) |
7799b7b3 UD |
31 | { |
32 | __real__ res = INFINITY; | |
33 | __imag__ res = __copysignl (0.0, __imag__ x); | |
34 | } | |
35 | else | |
36 | { | |
37 | long double den = (__real__ x * __real__ x + __imag__ x * __imag__ x | |
38 | + 1.0); | |
39 | ||
40 | __real__ res = (2.0 * __real__ x) / den; | |
41 | __imag__ res = (2.0 * __imag__ x) / den; | |
42 | } | |
43 | ||
44 | return res; | |
45 | } | |
46 | weak_alias (__cprojl, cprojl) |