1 /* $OpenBSD: s_ctanh.c,v 1.6 2013/07/03 04:46:36 espie 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 /* ctanh 19 * 20 * Complex hyperbolic tangent 21 * 22 * 23 * 24 * SYNOPSIS: 25 * 26 * double complex ctanh(); 27 * double complex z, w; 28 * 29 * w = ctanh (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 <float.h> 47 #include <math.h> 48 49 double complex 50 ctanh(double complex z) 51 { 52 double complex w; 53 double x, y, d; 54 55 x = creal(z); 56 y = cimag(z); 57 d = cosh (2.0 * x) + cos (2.0 * y); 58 w = sinh (2.0 * x) / d + (sin (2.0 * y) / d) * I; 59 return (w); 60 } 61 62 #if LDBL_MANT_DIG == DBL_MANT_DIG 63 __strong_alias(ctanhl, ctanh); 64 #endif /* LDBL_MANT_DIG == DBL_MANT_DIG */ 65