1/*-
2 * Copyright (c) 2011 David Schultz
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice unmodified, this list of conditions, and the following
10 *    disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27/*
28 * Hyperbolic tangent of a complex argument z.  See s_ctanh.c for details.
29 */
30
31#include <sys/cdefs.h>
32__FBSDID("$FreeBSD$");
33
34#include <complex.h>
35#include <math.h>
36
37#include "math_private.h"
38
39float complex
40ctanhf(float complex z)
41{
42	float x, y;
43	float t, beta, s, rho, denom;
44	uint32_t hx, ix;
45
46	x = crealf(z);
47	y = cimagf(z);
48
49	GET_FLOAT_WORD(hx, x);
50	ix = hx & 0x7fffffff;
51
52	if (ix >= 0x7f800000) {
53		if (ix & 0x7fffff)
54			return (cpackf(x, (y == 0 ? y : x * y)));
55		SET_FLOAT_WORD(x, hx - 0x40000000);
56		return (cpackf(x,
57		    copysignf(0, isinf(y) ? y : sinf(y) * cosf(y))));
58	}
59
60	if (!isfinite(y))
61		return (cpackf(y - y, y - y));
62
63	if (ix >= 0x41300000) {	/* x >= 11 */
64		float exp_mx = expf(-fabsf(x));
65		return (cpackf(copysignf(1, x),
66		    4 * sinf(y) * cosf(y) * exp_mx * exp_mx));
67	}
68
69	t = tanf(y);
70	beta = 1.0 + t * t;
71	s = sinhf(x);
72	rho = sqrtf(1 + s * s);
73	denom = 1 + beta * s * s;
74	return (cpackf((beta * rho * s) / denom, t / denom));
75}
76
77float complex
78ctanf(float complex z)
79{
80
81	z = ctanhf(cpackf(-cimagf(z), crealf(z)));
82	return (cpackf(cimagf(z), -crealf(z)));
83}
84
85