125c28e83SPiotr Jasiukajtis /* 225c28e83SPiotr Jasiukajtis * CDDL HEADER START 325c28e83SPiotr Jasiukajtis * 425c28e83SPiotr Jasiukajtis * The contents of this file are subject to the terms of the 525c28e83SPiotr Jasiukajtis * Common Development and Distribution License (the "License"). 625c28e83SPiotr Jasiukajtis * You may not use this file except in compliance with the License. 725c28e83SPiotr Jasiukajtis * 825c28e83SPiotr Jasiukajtis * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 925c28e83SPiotr Jasiukajtis * or http://www.opensolaris.org/os/licensing. 1025c28e83SPiotr Jasiukajtis * See the License for the specific language governing permissions 1125c28e83SPiotr Jasiukajtis * and limitations under the License. 1225c28e83SPiotr Jasiukajtis * 1325c28e83SPiotr Jasiukajtis * When distributing Covered Code, include this CDDL HEADER in each 1425c28e83SPiotr Jasiukajtis * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 1525c28e83SPiotr Jasiukajtis * If applicable, add the following below this CDDL HEADER, with the 1625c28e83SPiotr Jasiukajtis * fields enclosed by brackets "[]" replaced with your own identifying 1725c28e83SPiotr Jasiukajtis * information: Portions Copyright [yyyy] [name of copyright owner] 1825c28e83SPiotr Jasiukajtis * 1925c28e83SPiotr Jasiukajtis * CDDL HEADER END 2025c28e83SPiotr Jasiukajtis */ 2125c28e83SPiotr Jasiukajtis 2225c28e83SPiotr Jasiukajtis /* 2325c28e83SPiotr Jasiukajtis * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 2425c28e83SPiotr Jasiukajtis */ 2525c28e83SPiotr Jasiukajtis /* 2625c28e83SPiotr Jasiukajtis * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 2725c28e83SPiotr Jasiukajtis * Use is subject to license terms. 2825c28e83SPiotr Jasiukajtis */ 2925c28e83SPiotr Jasiukajtis 30*ddc0e0b5SRichard Lowe #pragma weak __atanhl = atanhl 3125c28e83SPiotr Jasiukajtis 3225c28e83SPiotr Jasiukajtis #include "libm.h" 3325c28e83SPiotr Jasiukajtis 3425c28e83SPiotr Jasiukajtis #define GENERIC long double 3525c28e83SPiotr Jasiukajtis #define ATANH atanhl 3625c28e83SPiotr Jasiukajtis 3725c28e83SPiotr Jasiukajtis /* ATANH(x) 3825c28e83SPiotr Jasiukajtis * 1 2x x 3925c28e83SPiotr Jasiukajtis * ATANH(x) = --- * LOG(1 + -------) = 0.5 * LOG1P(2 * --------) 4025c28e83SPiotr Jasiukajtis * 2 1 - x 1 - x 4125c28e83SPiotr Jasiukajtis * Note: to guarantee ATANH(-x) = -ATANH(x), we use 4225c28e83SPiotr Jasiukajtis * sign(x) |x| 4325c28e83SPiotr Jasiukajtis * ATANH(x) = ------- * LOG1P(2*-------). 4425c28e83SPiotr Jasiukajtis * 2 1 - |x| 4525c28e83SPiotr Jasiukajtis * 4625c28e83SPiotr Jasiukajtis * Special cases: 4725c28e83SPiotr Jasiukajtis * ATANH(x) is NaN if |x| > 1 with signal; 4825c28e83SPiotr Jasiukajtis * ATANH(NaN) is that NaN with no signal; 4925c28e83SPiotr Jasiukajtis * ATANH(+-1) is +-INF with signal. 5025c28e83SPiotr Jasiukajtis * 5125c28e83SPiotr Jasiukajtis */ 5225c28e83SPiotr Jasiukajtis 5325c28e83SPiotr Jasiukajtis #define FABS fabsl 5425c28e83SPiotr Jasiukajtis #define LOG1P log1pl 5525c28e83SPiotr Jasiukajtis #define COPYSIGN copysignl 5625c28e83SPiotr Jasiukajtis 5725c28e83SPiotr Jasiukajtis 5825c28e83SPiotr Jasiukajtis extern GENERIC FABS(),LOG1P(),COPYSIGN(); 5925c28e83SPiotr Jasiukajtis 6025c28e83SPiotr Jasiukajtis static GENERIC 6125c28e83SPiotr Jasiukajtis zero = (GENERIC) 0.0, 6225c28e83SPiotr Jasiukajtis half = (GENERIC) 0.5, 6325c28e83SPiotr Jasiukajtis one = (GENERIC) 1.0; 6425c28e83SPiotr Jasiukajtis 6525c28e83SPiotr Jasiukajtis GENERIC ATANH(x) 6625c28e83SPiotr Jasiukajtis GENERIC x; 6725c28e83SPiotr Jasiukajtis { 6825c28e83SPiotr Jasiukajtis GENERIC t; 6925c28e83SPiotr Jasiukajtis t = FABS(x); 7025c28e83SPiotr Jasiukajtis if (t == one) return x/zero; 7125c28e83SPiotr Jasiukajtis t = t/(one-t); 7225c28e83SPiotr Jasiukajtis return COPYSIGN(half,x)*LOG1P(t+t); 7325c28e83SPiotr Jasiukajtis } 74