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view libs/commons-math-2.1/docs/apidocs/src-html/org/apache/commons/math/ode/nonstiff/GillIntegrator.html @ 13:cbf34dd4d7e6
commons-math-2.1 added
| author | dwinter |
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| date | Tue, 04 Jan 2011 10:02:07 +0100 |
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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> <a name="line.17"></a> <FONT color="green">018</FONT> package org.apache.commons.math.ode.nonstiff;<a name="line.18"></a> <FONT color="green">019</FONT> <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 class implements the Gill fourth order Runge-Kutta<a name="line.22"></a> <FONT color="green">023</FONT> * integrator for Ordinary Differential Equations .<a name="line.23"></a> <FONT color="green">024</FONT> <a name="line.24"></a> <FONT color="green">025</FONT> * <p>This method is an explicit Runge-Kutta method, its Butcher-array<a name="line.25"></a> <FONT color="green">026</FONT> * is the following one :<a name="line.26"></a> <FONT color="green">027</FONT> * <pre><a name="line.27"></a> <FONT color="green">028</FONT> * 0 | 0 0 0 0<a name="line.28"></a> <FONT color="green">029</FONT> * 1/2 | 1/2 0 0 0<a name="line.29"></a> <FONT color="green">030</FONT> * 1/2 | (q-1)/2 (2-q)/2 0 0<a name="line.30"></a> <FONT color="green">031</FONT> * 1 | 0 -q/2 (2+q)/2 0<a name="line.31"></a> <FONT color="green">032</FONT> * |-------------------------------<a name="line.32"></a> <FONT color="green">033</FONT> * | 1/6 (2-q)/6 (2+q)/6 1/6<a name="line.33"></a> <FONT color="green">034</FONT> * </pre><a name="line.34"></a> <FONT color="green">035</FONT> * where q = sqrt(2)</p><a name="line.35"></a> <FONT color="green">036</FONT> *<a name="line.36"></a> <FONT color="green">037</FONT> * @see EulerIntegrator<a name="line.37"></a> <FONT color="green">038</FONT> * @see ClassicalRungeKuttaIntegrator<a name="line.38"></a> <FONT color="green">039</FONT> * @see MidpointIntegrator<a name="line.39"></a> <FONT color="green">040</FONT> * @see ThreeEighthesIntegrator<a name="line.40"></a> <FONT color="green">041</FONT> * @version $Revision: 810196 $ $Date: 2009-09-01 15:47:46 -0400 (Tue, 01 Sep 2009) $<a name="line.41"></a> <FONT color="green">042</FONT> * @since 1.2<a name="line.42"></a> <FONT color="green">043</FONT> */<a name="line.43"></a> <FONT color="green">044</FONT> <a name="line.44"></a> <FONT color="green">045</FONT> public class GillIntegrator extends RungeKuttaIntegrator {<a name="line.45"></a> <FONT color="green">046</FONT> <a name="line.46"></a> <FONT color="green">047</FONT> /** Time steps Butcher array. */<a name="line.47"></a> <FONT color="green">048</FONT> private static final double[] STATIC_C = {<a name="line.48"></a> <FONT color="green">049</FONT> 1.0 / 2.0, 1.0 / 2.0, 1.0<a name="line.49"></a> <FONT color="green">050</FONT> };<a name="line.50"></a> <FONT color="green">051</FONT> <a name="line.51"></a> <FONT color="green">052</FONT> /** Internal weights Butcher array. */<a name="line.52"></a> <FONT color="green">053</FONT> private static final double[][] STATIC_A = {<a name="line.53"></a> <FONT color="green">054</FONT> { 1.0 / 2.0 },<a name="line.54"></a> <FONT color="green">055</FONT> { (Math.sqrt(2.0) - 1.0) / 2.0, (2.0 - Math.sqrt(2.0)) / 2.0 },<a name="line.55"></a> <FONT color="green">056</FONT> { 0.0, -Math.sqrt(2.0) / 2.0, (2.0 + Math.sqrt(2.0)) / 2.0 }<a name="line.56"></a> <FONT color="green">057</FONT> };<a name="line.57"></a> <FONT color="green">058</FONT> <a name="line.58"></a> <FONT color="green">059</FONT> /** Propagation weights Butcher array. */<a name="line.59"></a> <FONT color="green">060</FONT> private static final double[] STATIC_B = {<a name="line.60"></a> <FONT color="green">061</FONT> 1.0 / 6.0, (2.0 - Math.sqrt(2.0)) / 6.0, (2.0 + Math.sqrt(2.0)) / 6.0, 1.0 / 6.0<a name="line.61"></a> <FONT color="green">062</FONT> };<a name="line.62"></a> <FONT color="green">063</FONT> <a name="line.63"></a> <FONT color="green">064</FONT> /** Simple constructor.<a name="line.64"></a> <FONT color="green">065</FONT> * Build a fourth-order Gill integrator with the given step.<a name="line.65"></a> <FONT color="green">066</FONT> * @param step integration step<a name="line.66"></a> <FONT color="green">067</FONT> */<a name="line.67"></a> <FONT color="green">068</FONT> public GillIntegrator(final double step) {<a name="line.68"></a> <FONT color="green">069</FONT> super("Gill", STATIC_C, STATIC_A, STATIC_B, new GillStepInterpolator(), step);<a name="line.69"></a> <FONT color="green">070</FONT> }<a name="line.70"></a> <FONT color="green">071</FONT> <a name="line.71"></a> <FONT color="green">072</FONT> }<a name="line.72"></a> </PRE> </BODY> </HTML>