Mercurial > hg > de.mpg.mpiwg.itgroup.digilib.plugin
view libs/commons-math-2.1/docs/apidocs/src-html/org/apache/commons/math/special/Erf.html @ 28:0205c3f41d1d default tip
repackaging (separate textgridlab and dgilib local parts more rigorously
author | dwinter |
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date | Fri, 24 Aug 2012 09:42:57 +0200 |
parents | cbf34dd4d7e6 |
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<HTML> <BODY BGCOLOR="white"> <PRE> <FONT color="green">001</FONT> /*<a name="line.1"></a> <FONT color="green">002</FONT> * Licensed to the Apache Software Foundation (ASF) under one or more<a name="line.2"></a> <FONT color="green">003</FONT> * contributor license agreements. See the NOTICE file distributed with<a name="line.3"></a> <FONT color="green">004</FONT> * this work for additional information regarding copyright ownership.<a name="line.4"></a> <FONT color="green">005</FONT> * The ASF licenses this file to You under the Apache License, Version 2.0<a name="line.5"></a> <FONT color="green">006</FONT> * (the "License"); you may not use this file except in compliance with<a name="line.6"></a> <FONT color="green">007</FONT> * the License. You may obtain a copy of the License at<a name="line.7"></a> <FONT color="green">008</FONT> *<a name="line.8"></a> <FONT color="green">009</FONT> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.9"></a> <FONT color="green">010</FONT> *<a name="line.10"></a> <FONT color="green">011</FONT> * Unless required by applicable law or agreed to in writing, software<a name="line.11"></a> <FONT color="green">012</FONT> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.12"></a> <FONT color="green">013</FONT> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.13"></a> <FONT color="green">014</FONT> * See the License for the specific language governing permissions and<a name="line.14"></a> <FONT color="green">015</FONT> * limitations under the License.<a name="line.15"></a> <FONT color="green">016</FONT> */<a name="line.16"></a> <FONT color="green">017</FONT> package org.apache.commons.math.special;<a name="line.17"></a> <FONT color="green">018</FONT> <a name="line.18"></a> <FONT color="green">019</FONT> import org.apache.commons.math.MathException;<a name="line.19"></a> <FONT color="green">020</FONT> <a name="line.20"></a> <FONT color="green">021</FONT> /**<a name="line.21"></a> <FONT color="green">022</FONT> * This is a utility class that provides computation methods related to the<a name="line.22"></a> <FONT color="green">023</FONT> * error functions.<a name="line.23"></a> <FONT color="green">024</FONT> *<a name="line.24"></a> <FONT color="green">025</FONT> * @version $Revision: 811685 $ $Date: 2009-09-05 13:36:48 -0400 (Sat, 05 Sep 2009) $<a name="line.25"></a> <FONT color="green">026</FONT> */<a name="line.26"></a> <FONT color="green">027</FONT> public class Erf {<a name="line.27"></a> <FONT color="green">028</FONT> <a name="line.28"></a> <FONT color="green">029</FONT> /**<a name="line.29"></a> <FONT color="green">030</FONT> * Default constructor. Prohibit instantiation.<a name="line.30"></a> <FONT color="green">031</FONT> */<a name="line.31"></a> <FONT color="green">032</FONT> private Erf() {<a name="line.32"></a> <FONT color="green">033</FONT> super();<a name="line.33"></a> <FONT color="green">034</FONT> }<a name="line.34"></a> <FONT color="green">035</FONT> <a name="line.35"></a> <FONT color="green">036</FONT> /**<a name="line.36"></a> <FONT color="green">037</FONT> * Returns the error function erf(x).<a name="line.37"></a> <FONT color="green">038</FONT> *<a name="line.38"></a> <FONT color="green">039</FONT> * The implementation of this method is based on:<a name="line.39"></a> <FONT color="green">040</FONT> * <ul><a name="line.40"></a> <FONT color="green">041</FONT> * <li><a name="line.41"></a> <FONT color="green">042</FONT> * <a href="http://mathworld.wolfram.com/Erf.html"><a name="line.42"></a> <FONT color="green">043</FONT> * Erf</a>, equation (3).</li><a name="line.43"></a> <FONT color="green">044</FONT> * </ul><a name="line.44"></a> <FONT color="green">045</FONT> *<a name="line.45"></a> <FONT color="green">046</FONT> * @param x the value.<a name="line.46"></a> <FONT color="green">047</FONT> * @return the error function erf(x)<a name="line.47"></a> <FONT color="green">048</FONT> * @throws MathException if the algorithm fails to converge.<a name="line.48"></a> <FONT color="green">049</FONT> */<a name="line.49"></a> <FONT color="green">050</FONT> public static double erf(double x) throws MathException {<a name="line.50"></a> <FONT color="green">051</FONT> double ret = Gamma.regularizedGammaP(0.5, x * x, 1.0e-15, 10000);<a name="line.51"></a> <FONT color="green">052</FONT> if (x < 0) {<a name="line.52"></a> <FONT color="green">053</FONT> ret = -ret;<a name="line.53"></a> <FONT color="green">054</FONT> }<a name="line.54"></a> <FONT color="green">055</FONT> return ret;<a name="line.55"></a> <FONT color="green">056</FONT> }<a name="line.56"></a> <FONT color="green">057</FONT> }<a name="line.57"></a> </PRE> </BODY> </HTML>