compiler/stdc/math/s_cexpl.c

   1 /*      $OpenBSD: s_cexpl.c,v 1.2 2011/07/20 19:28:33 martynas Exp $    */
   2
   3 /*
   4  * Copyright (c) 2008 Stephen L. Moshier <steve@moshier.net>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 /*                                                      cexpl()
  20  *
  21  *      Complex exponential function
  22  *
  23  *
  24  *
  25  * SYNOPSIS:
  26  *
  27  * long double complex cexpl();
  28  * long double complex z, w;
  29  *
  30  * w = cexpl( z );
  31  *
  32  *
  33  *
  34  * DESCRIPTION:
  35  *
  36  * Returns the exponential of the complex argument z
  37  * into the complex result w.
  38  *
  39  * If
  40  *     z = x + iy,
  41  *     r = exp(x),
  42  *
  43  * then
  44  *
  45  *     w = r cos y + i r sin y.
  46  *
  47  *
  48  * ACCURACY:
  49  *
  50  *                      Relative error:
  51  * arithmetic   domain     # trials      peak         rms
  52  *    DEC       -10,+10      8700       3.7e-17     1.1e-17
  53  *    IEEE      -10,+10     30000       3.0e-16     8.7e-17
  54  *
  55  */
  56
  57 #include <complex.h>
  58 #include "math.h"
  59
  60 long double complex
  61 cexpl(long double complex z)
  62 {
  63         long double complex w;
  64         long double r;
  65
  66         r = expl(creall(z));
  67         w = r * cosl(cimagl(z)) + (r * sinl(cimagl(z))) * I;
  68         return (w);
  69 }