1 /* origin: OpenBSD /usr/src/lib/libm/src/s_cpow.c */
3 * Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net>
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.
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.
18 * Complex power function
23 * double complex cpow();
24 * double complex a, z, w;
31 * Raises complex A to the complex Zth power.
32 * Definition is per AMS55 # 4.2.8,
33 * analytically equivalent to cpow(a,z) = cexp(z clog(a)).
38 * arithmetic domain # trials peak rms
39 * IEEE -10,+10 30000 9.4e-15 1.5e-15
44 double complex cpow(double complex a, double complex z)
46 double x, y, r, theta, absa, arga;
57 r = r * exp(-y * arga);
58 theta += y * log(absa);
60 return cpack(r * cos(theta), (r * sin(theta)));