acosh.c revision ddc0e0b53c661f6e439e3b7072b3ef353eadb4af
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * CDDL HEADER START
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * The contents of this file are subject to the terms of the
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * Common Development and Distribution License (the "License").
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * You may not use this file except in compliance with the License.
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * See the License for the specific language governing permissions
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adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * When distributing Covered Code, include this CDDL HEADER in each
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * If applicable, add the following below this CDDL HEADER, with the
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adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * information: Portions Copyright [yyyy] [name of copyright owner]
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * CDDL HEADER END
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * Use is subject to license terms.
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg/* INDENT OFF */
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * acosh(x)
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * Method :
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * Based on
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * acosh(x) = log [ x + sqrt(x*x-1) ]
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * acosh(x) := log(x)+ln2, if x is large; else
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * acosh(x) := log(2x-1/(sqrt(x*x-1)+x)) if x > 2; else
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * acosh(x) := log1p(t+sqrt(2.0*t+t*t)); where t = x-1.
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * Special cases:
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * acosh(x) is NaN with signal if x < 1.
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg * acosh(NaN) is NaN without signal.
adecd3c68045d04dc367d30faf2eb5cac1f45d5adg/* INDENT ON */
#include "libm_macros.h"
#include <math.h>
acosh(double x) {
int hx;
if (isnan(x))
#if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN)
#if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN)
t = x - one;