1*05a0b428SJohn Marino /* $OpenBSD: s_cacosl.c,v 1.3 2011/07/20 21:02:51 martynas Exp $ */
2*05a0b428SJohn Marino
3*05a0b428SJohn Marino /*
4*05a0b428SJohn Marino * Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net>
5*05a0b428SJohn Marino *
6*05a0b428SJohn Marino * Permission to use, copy, modify, and distribute this software for any
7*05a0b428SJohn Marino * purpose with or without fee is hereby granted, provided that the above
8*05a0b428SJohn Marino * copyright notice and this permission notice appear in all copies.
9*05a0b428SJohn Marino *
10*05a0b428SJohn Marino * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11*05a0b428SJohn Marino * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12*05a0b428SJohn Marino * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13*05a0b428SJohn Marino * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14*05a0b428SJohn Marino * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15*05a0b428SJohn Marino * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16*05a0b428SJohn Marino * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17*05a0b428SJohn Marino */
18*05a0b428SJohn Marino
19*05a0b428SJohn Marino /* cacosl()
20*05a0b428SJohn Marino *
21*05a0b428SJohn Marino * Complex circular arc cosine
22*05a0b428SJohn Marino *
23*05a0b428SJohn Marino *
24*05a0b428SJohn Marino *
25*05a0b428SJohn Marino * SYNOPSIS:
26*05a0b428SJohn Marino *
27*05a0b428SJohn Marino * long double complex cacosl();
28*05a0b428SJohn Marino * long double complex z, w;
29*05a0b428SJohn Marino *
30*05a0b428SJohn Marino * w = cacosl( z );
31*05a0b428SJohn Marino *
32*05a0b428SJohn Marino *
33*05a0b428SJohn Marino *
34*05a0b428SJohn Marino * DESCRIPTION:
35*05a0b428SJohn Marino *
36*05a0b428SJohn Marino *
37*05a0b428SJohn Marino * w = arccos z = PI/2 - arcsin z.
38*05a0b428SJohn Marino *
39*05a0b428SJohn Marino *
40*05a0b428SJohn Marino *
41*05a0b428SJohn Marino *
42*05a0b428SJohn Marino * ACCURACY:
43*05a0b428SJohn Marino *
44*05a0b428SJohn Marino * Relative error:
45*05a0b428SJohn Marino * arithmetic domain # trials peak rms
46*05a0b428SJohn Marino * DEC -10,+10 5200 1.6e-15 2.8e-16
47*05a0b428SJohn Marino * IEEE -10,+10 30000 1.8e-14 2.2e-15
48*05a0b428SJohn Marino */
49*05a0b428SJohn Marino
50*05a0b428SJohn Marino #include <complex.h>
51*05a0b428SJohn Marino #include <math.h>
52*05a0b428SJohn Marino
53*05a0b428SJohn Marino static const long double PIO2L = 1.570796326794896619231321691639751442098585L;
54*05a0b428SJohn Marino
55*05a0b428SJohn Marino long double complex
cacosl(long double complex z)56*05a0b428SJohn Marino cacosl(long double complex z)
57*05a0b428SJohn Marino {
58*05a0b428SJohn Marino long double complex w;
59*05a0b428SJohn Marino
60*05a0b428SJohn Marino w = casinl(z);
61*05a0b428SJohn Marino w = (PIO2L - creall(w)) - cimagl(w) * I;
62*05a0b428SJohn Marino return (w);
63*05a0b428SJohn Marino }
64