25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * CDDL HEADER START
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * The contents of this file are subject to the terms of the
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Common Development and Distribution License (the "License").
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * You may not use this file except in compliance with the License.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * or http://www.opensolaris.org/os/licensing.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * See the License for the specific language governing permissions
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * and limitations under the License.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * When distributing Covered Code, include this CDDL HEADER in each
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * If applicable, add the following below this CDDL HEADER, with the
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * fields enclosed by brackets "[]" replaced with your own identifying
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * information: Portions Copyright [yyyy] [name of copyright owner]
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * CDDL HEADER END
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Use is subject to license terms.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
ddc0e0b53c661f6e439e3b7072b3ef353eadb4afRichard Lowe#pragma weak __atanhl = atanhl
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#include "libm.h"
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define GENERIC long double
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define ATANH atanhl
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/* ATANH(x)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * 1 2x x
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * ATANH(x) = --- * LOG(1 + -------) = 0.5 * LOG1P(2 * --------)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * 2 1 - x 1 - x
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Note: to guarantee ATANH(-x) = -ATANH(x), we use
ddc0e0b53c661f6e439e3b7072b3ef353eadb4afRichard Lowe * sign(x) |x|
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * ATANH(x) = ------- * LOG1P(2*-------).
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * 2 1 - |x|
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Special cases:
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * ATANH(x) is NaN if |x| > 1 with signal;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * ATANH(NaN) is that NaN with no signal;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * ATANH(+-1) is +-INF with signal.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define FABS fabsl
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define LOG1P log1pl
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define COPYSIGN copysignl
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisextern GENERIC FABS(),LOG1P(),COPYSIGN();
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisstatic GENERIC
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtiszero = (GENERIC) 0.0,
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtishalf = (GENERIC) 0.5,
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisone = (GENERIC) 1.0;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr JasiukajtisGENERIC ATANH(x)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr JasiukajtisGENERIC x;
ddc0e0b53c661f6e439e3b7072b3ef353eadb4afRichard Lowe{
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis GENERIC t;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis t = FABS(x);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (t == one) return x/zero;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis t = t/(one-t);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis return COPYSIGN(half,x)*LOG1P(t+t);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis}