1 /* $OpenBSD: s_ctanh.c,v 1.2 2011/07/08 19:25:31 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 /* LINTLIBRARY */ 19 20 /* ctanh 21 * 22 * Complex hyperbolic tangent 23 * 24 * 25 * 26 * SYNOPSIS: 27 * 28 * double complex ctanh(); 29 * double complex z, w; 30 * 31 * w = ctanh (z); 32 * 33 * 34 * 35 * DESCRIPTION: 36 * 37 * tanh z = (sinh 2x + i sin 2y) / (cosh 2x + cos 2y) . 38 * 39 * ACCURACY: 40 * 41 * Relative error: 42 * arithmetic domain # trials peak rms 43 * IEEE -10,+10 30000 1.7e-14 2.4e-16 44 * 45 */ 46 47 #include <sys/cdefs.h> 48 #include <complex.h> 49 #include <float.h> 50 #include <math.h> 51 52 double complex 53 ctanh(double complex z) 54 { 55 double complex w; 56 double x, y, d; 57 58 x = creal(z); 59 y = cimag(z); 60 d = cosh (2.0 * x) + cos (2.0 * y); 61 w = sinh (2.0 * x) / d + (sin (2.0 * y) / d) * I; 62 return (w); 63 } 64 65 #if LDBL_MANT_DIG == 53 66 #ifdef lint 67 /* PROTOLIB1 */ 68 long double complex ctanhl(long double complex); 69 #else /* lint */ 70 __weak_alias(ctanhl, ctanh); 71 #endif /* lint */ 72 #endif /* LDBL_MANT_DIG == 53 */ 73