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 } 60