1 /* $NetBSD: casinf.c,v 1.1 2007/08/20 16:01:31 drochner Exp $ */
2
3 /*-
4 * Copyright (c) 2007 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software written by Stephen L. Moshier.
8 * It is redistributed by the NetBSD Foundation by permission of the author.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 *
31 * imported and modified include for newlib 2010/10/03
32 * Marco Atzeri <marco_atzeri@yahoo.it>
33 */
34
35 #include <complex.h>
36 #include <math.h>
37
38 #ifdef __weak_alias
__weak_alias(casinf,_casinf)39 __weak_alias(casinf, _casinf)
40 #endif
41
42 float complex
43 casinf(float complex z)
44 {
45 float complex w;
46 float complex ca, ct, zz, z2;
47 float x, y;
48
49 x = crealf(z);
50 y = cimagf(z);
51
52 #if 0 /* MD: test is incorrect, casin(>1) is defined */
53 if (y == 0.0f) {
54 if (fabsf(x) > 1.0) {
55 w = M_PI_2 + 0.0f * I;
56 #if 0
57 mtherr ("casin", DOMAIN);
58 #endif
59 } else {
60 w = asinf(x) + 0.0f * I;
61 }
62 return w;
63 }
64 #endif
65
66 /* Power series expansion */
67 /*
68 b = cabsf(z);
69 if( b < 0.125 )
70 {
71 z2.r = (x - y) * (x + y);
72 z2.i = 2.0 * x * y;
73
74 cn = 1.0;
75 n = 1.0;
76 ca.r = x;
77 ca.i = y;
78 sum.r = x;
79 sum.i = y;
80 do
81 {
82 ct.r = z2.r * ca.r - z2.i * ca.i;
83 ct.i = z2.r * ca.i + z2.i * ca.r;
84 ca.r = ct.r;
85 ca.i = ct.i;
86
87 cn *= n;
88 n += 1.0;
89 cn /= n;
90 n += 1.0;
91 b = cn/n;
92
93 ct.r *= b;
94 ct.i *= b;
95 sum.r += ct.r;
96 sum.i += ct.i;
97 b = fabsf(ct.r) + fabsf(ct.i);
98 }
99 while( b > MACHEP );
100 w->r = sum.r;
101 w->i = sum.i;
102 return;
103 }
104 */
105
106
107 ca = x + y * I;
108 ct = ca * I;
109 /* sqrt( 1 - z*z) */
110 /* cmul( &ca, &ca, &zz ) */
111 /*x * x - y * y */
112 zz = (x - y) * (x + y) + (2.0f * x * y) * I;
113
114 zz = 1.0f - crealf(zz) - cimagf(zz) * I;
115 z2 = csqrtf(zz);
116
117 zz = ct + z2;
118 zz = clogf(zz);
119 /* multiply by 1/i = -i */
120 w = zz * (-1.0f * I);
121 return w;
122 }
123
