1/*	$OpenBSD: s_ctanhl.c,v 1.2 2011/07/20 19:28:33 martynas Exp $	*/
2
3/*
4 * Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19/*							ctanhl
20 *
21 *	Complex hyperbolic tangent
22 *
23 *
24 *
25 * SYNOPSIS:
26 *
27 * long double complex ctanhl();
28 * long double complex z, w;
29 *
30 * w = ctanhl (z);
31 *
32 *
33 *
34 * DESCRIPTION:
35 *
36 * tanh z = (sinh 2x  +  i sin 2y) / (cosh 2x + cos 2y) .
37 *
38 * ACCURACY:
39 *
40 *                      Relative error:
41 * arithmetic   domain     # trials      peak         rms
42 *    IEEE      -10,+10     30000       1.7e-14     2.4e-16
43 *
44 */
45
46#include <complex.h>
47#include <math.h>
48
49long double complex
50ctanhl(long double complex z)
51{
52	long double complex w;
53	long double x, y, d;
54
55	x = creall(z);
56	y = cimagl(z);
57	d = coshl(2.0L * x) + cosl(2.0L * y);
58	w = sinhl(2.0L * x) / d + (sinl(2.0L * y) / d) * I;
59	return (w);
60}
61