text: /*-
   * Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net>
   *
   * Permission to use, copy, modify, and distribute this software for any
   * purpose with or without fee is hereby granted, provided that the above
   * copyright notice and this permission notice appear in all copies.
   *
   * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   */
  
  /*							cpow
   *
   *	Complex power function
   *
   *
   *
   * SYNOPSIS:
   *
   * double complex cpow();
   * double complex a, z, w;
   *
   * w = cpow (a, z);
   *
   *
   *
   * DESCRIPTION:
   *
   * Raises complex A to the complex Zth power.
   * Definition is per AMS55 # 4.2.8,
   * analytically equivalent to cpow(a,z) = cexp(z clog(a)).
   *
   * ACCURACY:
   *
   *                      Relative error:
   * arithmetic   domain     # trials      peak         rms
   *    IEEE      -10,+10     30000       9.4e-15     1.5e-15
   *
   */
  
  #include <sys/cdefs.h>
  __FBSDID("$FreeBSD$");
  
  #include <complex.h>
  #include <float.h>
  #include <math.h>
  #include "math_private.h"
  
  double complex
  cpow(double complex a, double complex z)
  {
  	double complex w;
  	double x, y, r, theta, absa, arga;
  
  	x = creal (z);
  	y = cimag (z);
  	absa = cabs (a);
  	if (absa == 0.0) {
  		return (CMPLX(0.0, 0.0));
  	}
  	arga = carg (a);
  	r = pow (absa, x);
  	theta = x * arga;
  	if (y != 0.0) {
  		r = r * exp (-y * arga);
  		theta = theta + y * log (absa);
  	}
  	w = CMPLX(r * cos (theta),  r * sin (theta));
  	return (w);
  }
  