1 /*	$OpenBSD: s_catanh.c,v 1.6 2013/07/03 04:46:36 espie Exp $	*/
2 /*
3  * Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 /*							catanh
19  *
20  *	Complex inverse hyperbolic tangent
21  *
22  *
23  *
24  * SYNOPSIS:
25  *
26  * double complex catanh();
27  * double complex z, w;
28  *
29  * w = catanh (z);
30  *
31  *
32  *
33  * DESCRIPTION:
34  *
35  * Inverse tanh, equal to  -i catan (iz);
36  *
37  * ACCURACY:
38  *
39  *                      Relative error:
40  * arithmetic   domain     # trials      peak         rms
41  *    IEEE      -10,+10     30000       2.3e-16     6.2e-17
42  *
43  */
44 
45 #include <complex.h>
46 #include <float.h>
47 #include <math.h>
48 
49 double complex
50 catanh(double complex z)
51 {
52 	double complex w;
53 
54 	w = -1.0 * I * catan (z * I);
55 	return (w);
56 }
57 
58 #if	LDBL_MANT_DIG == DBL_MANT_DIG
59 __strong_alias(catanhl, catanh);
60 #endif	/* LDBL_MANT_DIG == DBL_MANT_DIG */
61