compiler/stdc/math/s_ctanf.c

   1 /*      $OpenBSD: s_ctanf.c,v 1.2 2011/07/20 19:28:33 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 /*                                                      ctanf()
  19  *
  20  *      Complex circular tangent
  21  *
  22  *
  23  *
  24  * SYNOPSIS:
  25  *
  26  * void ctanf();
  27  * cmplxf z, w;
  28  *
  29  * ctanf( &z, &w );
  30  *
  31  *
  32  *
  33  * DESCRIPTION:
  34  *
  35  * If
  36  *     z = x + iy,
  37  *
  38  * then
  39  *
  40  *           sin 2x  +  i sinh 2y
  41  *     w  =  --------------------.
  42  *            cos 2x  +  cosh 2y
  43  *
  44  * On the real axis the denominator is zero at odd multiples
  45  * of PI/2.  The denominator is evaluated by its Taylor
  46  * series near these points.
  47  *
  48  *
  49  * ACCURACY:
  50  *
  51  *                      Relative error:
  52  * arithmetic   domain     # trials      peak         rms
  53  *    IEEE      -10,+10     30000       3.3e-7       5.1e-8
  54  */
  55
  56 #include <complex.h>
  57 #include "math.h"
  58
  59 #include "math_private.h"
  60
  61 float complex
  62 ctanf(float complex z)
  63 {
  64         z = ctanhf(CMPLXF(cimagf(z), crealf(z)));
  65         return (CMPLXF(cimagf(z), crealf(z)));
  66 }