gonzui

    1: /*      $OpenBSD: s_cpow.c,v 1.2 2011/07/08 19:25:31 martynas 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: /* LINTLIBRARY */
   19: 
   20: /*                                                      cpow
   21:  *
   22:  *      Complex power function
   23:  *
   24:  *
   25:  *
   26:  * SYNOPSIS:
   27:  *
   28:  * double complex cpow();
   29:  * double complex a, z, w;
   30:  *
   31:  * w = cpow (a, z);
   32:  *
   33:  *
   34:  *
   35:  * DESCRIPTION:
   36:  *
   37:  * Raises complex A to the complex Zth power.
   38:  * Definition is per AMS55 # 4.2.8,
   39:  * analytically equivalent to cpow(a,z) = cexp(z clog(a)).
   40:  *
   41:  * ACCURACY:
   42:  *
   43:  *                      Relative error:
   44:  * arithmetic   domain     # trials      peak         rms
   45:  *    IEEE      -10,+10     30000       9.4e-15     1.5e-15
   46:  *
   47:  */
   48: 
   49: #include <sys/cdefs.h>
   50: #include <complex.h>
   51: #include <float.h>
   52: #include <math.h>
   53: 
   54: double complex
   55: cpow(double complex a, double complex z)
   56: {
   57:         double complex w;
   58:         double x, y, r, theta, absa, arga;
   59: 
   60:         x = creal (z);
   61:         y = cimag (z);
   62:         absa = cabs (a);
   63:         if (absa == 0.0) {
   64:                 return (0.0 + 0.0 * I);
   65:         }
   66:         arga = carg (a);
   67:         r = pow (absa, x);
   68:         theta = x * arga;
   69:         if (y != 0.0) {
   70:                 r = r * exp (-y * arga);
   71:                 theta = theta + y * log (absa);
   72:         }
   73:         w = r * cos (theta) + (r * sin (theta)) * I;
   74:         return (w);
   75: }
   76: 
   77: #if     LDBL_MANT_DIG == 53
   78: #ifdef  lint
   79: /* PROTOLIB1 */
   80: long double complex cpowl(long double complex, long double complex);
   81: #else   /* lint */
   82: __weak_alias(cpowl, cpow);
   83: #endif  /* lint */
   84: #endif  /* LDBL_MANT_DIG == 53 */