| Quellcodebibliothek Statistik Leitseite products/sources/formale Sprachen/Java/Openjdk/src/java.base/share/native/libfdlibm/ (Sun/Oracle ©) Datei vom 13.11.2022 mit Größe 2 kB |
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Quelle e_atanh.c Sprache: C |
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/*
* Copyright (c) 1998, 2001, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ /* __ieee754_atanh(x) * Method : * 1.Reduced x to positive by atanh(-x) = -atanh(x) * 2.For x>=0.5 * 1 2x x * atanh(x) = --- * log(1 + -------) = 0.5 * log1p(2 * --------) * 2 1 - x 1 - x * * For x<0.5 * atanh(x) = 0.5*log1p(2x+2x*x/(1-x)) * * Special cases: * atanh(x) is NaN if |x| > 1 with signal; * atanh(NaN) is that NaN with no signal; * atanh(+-1) is +-INF with signal. * */ #include "fdlibm.h" #ifdef __STDC__ static const double one = 1.0, huge = 1e300; #else static double one = 1.0, huge = 1e300; #endif static double zero = 0.0; #ifdef __STDC__ double __ieee754_atanh(double x) #else double __ieee754_atanh(x) double x; #endif { double t; int hx,ix; unsigned lx; hx = __HI(x); /* high word */ lx = __LO(x); /* low word */ ix = hx&0x7fffffff; if ((ix|((lx|(-lx))>>31))>0x3ff00000) /* |x|>1 */ return (x-x)/(x-x); if(ix==0x3ff00000) return x/zero; if(ix<0x3e300000&&(huge+x)>zero) return x; /* x<2**-28 */ __HI(x) = ix; /* x <- |x| */ if(ix<0x3fe00000) { /* x < 0.5 */ t = x+x; t = 0.5*log1p(t+t*x/(one-x)); } else t = 0.5*log1p((x+x)/(one-x)); if(hx>=0) return t; else return -t; } ¤ Dauer der Verarbeitung: 0.12 Sekunden (vorverarbeitet) ¤*© Formatika GbR, Deutschland |
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2026-03-28