1 |
|
|
/* $OpenBSD: s_cpowf.c,v 1.2 2010/07/18 18:42:26 guenther 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 |
|
|
/* cpowf |
19 |
|
|
* |
20 |
|
|
* Complex power function |
21 |
|
|
* |
22 |
|
|
* |
23 |
|
|
* |
24 |
|
|
* SYNOPSIS: |
25 |
|
|
* |
26 |
|
|
* float complex cpowf(); |
27 |
|
|
* float complex a, z, w; |
28 |
|
|
* |
29 |
|
|
* w = cpowf (a, z); |
30 |
|
|
* |
31 |
|
|
* |
32 |
|
|
* |
33 |
|
|
* DESCRIPTION: |
34 |
|
|
* |
35 |
|
|
* Raises complex A to the complex Zth power. |
36 |
|
|
* Definition is per AMS55 # 4.2.8, |
37 |
|
|
* analytically equivalent to cpow(a,z) = cexp(z clog(a)). |
38 |
|
|
* |
39 |
|
|
* ACCURACY: |
40 |
|
|
* |
41 |
|
|
* Relative error: |
42 |
|
|
* arithmetic domain # trials peak rms |
43 |
|
|
* IEEE -10,+10 30000 9.4e-15 1.5e-15 |
44 |
|
|
* |
45 |
|
|
*/ |
46 |
|
|
|
47 |
|
|
#include <complex.h> |
48 |
|
|
#include <math.h> |
49 |
|
|
|
50 |
|
|
float complex |
51 |
|
|
cpowf(float complex a, float complex z) |
52 |
|
|
{ |
53 |
|
|
float complex w; |
54 |
|
|
float x, y, r, theta, absa, arga; |
55 |
|
|
|
56 |
|
|
x = crealf(z); |
57 |
|
|
y = cimagf(z); |
58 |
|
|
absa = cabsf (a); |
59 |
|
|
if (absa == 0.0f) { |
60 |
|
|
return (0.0f + 0.0f * I); |
61 |
|
|
} |
62 |
|
|
arga = cargf (a); |
63 |
|
|
r = powf (absa, x); |
64 |
|
|
theta = x * arga; |
65 |
|
|
if (y != 0.0f) { |
66 |
|
|
r = r * expf (-y * arga); |
67 |
|
|
theta = theta + y * logf (absa); |
68 |
|
|
} |
69 |
|
|
w = r * cosf (theta) + (r * sinf (theta)) * I; |
70 |
|
|
return (w); |
71 |
|
|
} |