gonzui

    1: /*      $OpenBSD: s_ctanhf.c,v 1.2 2010/07/18 18:42:26 guenther 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: /*                                                      ctanhf
   19:  *
   20:  *      Complex hyperbolic tangent
   21:  *
   22:  *
   23:  *
   24:  * SYNOPSIS:
   25:  *
   26:  * float complex ctanhf();
   27:  * float complex z, w;
   28:  *
   29:  * w = ctanhf (z);
   30:  *
   31:  *
   32:  *
   33:  * DESCRIPTION:
   34:  *
   35:  * tanh z = (sinh 2x  +  i sin 2y) / (cosh 2x + cos 2y) .
   36:  *
   37:  * ACCURACY:
   38:  *
   39:  *                      Relative error:
   40:  * arithmetic   domain     # trials      peak         rms
   41:  *    IEEE      -10,+10     30000       1.7e-14     2.4e-16
   42:  *
   43:  */
   44: 
   45: #include <complex.h>
   46: #include <math.h>
   47: 
   48: float complex
   49: ctanhf(float complex z)
   50: {
   51:         float complex w;
   52:         float x, y, d;
   53: 
   54:         x = crealf(z);
   55:         y = cimagf(z);
   56:         d = coshf (2.0f * x) + cosf (2.0f * y);
   57:         w = sinhf (2.0f * x) / d  +  (sinf (2.0f * y) / d) * I;
   58:         return (w);
   59: }