
Commons Math example source code file (GillIntegrator.java)
The Commons Math GillIntegrator.java source code/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.commons.math.ode.nonstiff; /** * This class implements the Gill fourth order RungeKutta * integrator for Ordinary Differential Equations . * <p>This method is an explicit RungeKutta method, its Butcherarray * is the following one : * <pre> * 0  0 0 0 0 * 1/2  1/2 0 0 0 * 1/2  (q1)/2 (2q)/2 0 0 * 1  0 q/2 (2+q)/2 0 *  *  1/6 (2q)/6 (2+q)/6 1/6 * </pre> * where q = sqrt(2)</p> * * @see EulerIntegrator * @see ClassicalRungeKuttaIntegrator * @see MidpointIntegrator * @see ThreeEighthesIntegrator * @version $Revision: 810196 $ $Date: 20090901 15:47:46 0400 (Tue, 01 Sep 2009) $ * @since 1.2 */ public class GillIntegrator extends RungeKuttaIntegrator { /** Time steps Butcher array. */ private static final double[] STATIC_C = { 1.0 / 2.0, 1.0 / 2.0, 1.0 }; /** Internal weights Butcher array. */ private static final double[][] STATIC_A = { { 1.0 / 2.0 }, { (Math.sqrt(2.0)  1.0) / 2.0, (2.0  Math.sqrt(2.0)) / 2.0 }, { 0.0, Math.sqrt(2.0) / 2.0, (2.0 + Math.sqrt(2.0)) / 2.0 } }; /** Propagation weights Butcher array. */ private static final double[] STATIC_B = { 1.0 / 6.0, (2.0  Math.sqrt(2.0)) / 6.0, (2.0 + Math.sqrt(2.0)) / 6.0, 1.0 / 6.0 }; /** Simple constructor. * Build a fourthorder Gill integrator with the given step. * @param step integration step */ public GillIntegrator(final double step) { super("Gill", STATIC_C, STATIC_A, STATIC_B, new GillStepInterpolator(), step); } } Other Commons Math examples (source code examples)Here is a short list of links related to this Commons Math GillIntegrator.java source code file: 
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