xref: /illumos-gate/usr/src/lib/libm/common/complex/catanh.c (revision d48be21240dfd051b689384ce2b23479d757f2d8)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2011 Nexenta Systems, Inc.  All rights reserved.
24  */
25 /*
26  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
27  * Use is subject to license terms.
28  */
29 
30 #pragma weak __catanh = catanh
31 
32 /* INDENT OFF */
33 /*
34  * z := x + iy
35  * catanh(z)	= -i catan(iz)
36  *		= -i catan(-y+ix)
37  *		= (Im(catan(-y+ix)), -Re(catan(-y+ix)))
38  */
39 /* INDENT ON */
40 
41 #include "libm.h"
42 #include "complex_wrapper.h"
43 
44 dcomplex
45 catanh(dcomplex z) {
46 	double x, y;
47 	dcomplex ans, ct;
48 
49 	x = D_RE(z);
50 	y = D_IM(z);
51 	D_RE(z) = -y;
52 	D_IM(z) = x;
53 	ct = catan(z);
54 	D_RE(ans) = D_IM(ct);
55 	D_IM(ans) = -D_RE(ct);
56 	return (ans);
57 }
58