01 /*
02 * $Id: VdpolRKFSolution.java,v 1.3 2008/02/02 03:06:25 koga Exp $
03 *
04 * Copyright (C) 2004 Koga Laboratory. All rights reserved.
05 *
06 */
07 package matxbook.chap21;
08
09 import java.io.IOException;
10
11 import org.mklab.nfc.matrix.DoubleMatrix;
12 import org.mklab.nfc.matrix.Matrix;
13 import org.mklab.nfc.ode.DifferentialEquationSolver;
14 import org.mklab.nfc.ode.DifferentialEquation;
15 import org.mklab.nfc.ode.RungeKuttaFehlberg;
16 import org.mklab.nfc.util.Pause;
17 import org.mklab.tool.graph.gnuplot.Canvas;
18 import org.mklab.tool.graph.gnuplot.Gnuplot;
19
20
21 /**
22 * ヴァンデルポール方程式を4次のRKF法(5次のルンゲ・クッタ法)で解くクラスです。
23 *
24 * @author koga
25 * @version $Revision: 1.3 $, 2004/04/22
26 */
27 public class VdpolRKFSolution {
28
29 /**
30 * メインメソッド
31 *
32 * @param args コマンドライン引数
33 * @throws InterruptedException 強制終了された場合
34 * @throws IOException キーボードから入力できない場合
35 */
36 @SuppressWarnings("nls")
37 public static void main(String[] args) throws InterruptedException, IOException {
38 DifferentialEquation equation = new Vdpol();
39 Matrix x0 = new DoubleMatrix(new double[] {0, 0.25}).transpose();
40 DifferentialEquationSolver solver = new RungeKuttaFehlberg();
41 solver.setTimeStep(0.1);
42 solver.solve(equation, 0.0, 20.0, x0);
43 DoubleMatrix tt = solver.getTimeSeries();
44 DoubleMatrix xx = solver.getDifferentialSolution();
45
46 Gnuplot gnuplot = new Gnuplot();
47 Canvas canvas = gnuplot.createCanvas();
48 canvas.setHolding(true);
49 canvas.plot(tt, xx, new String[] {"x1", "x2"});
50 canvas.plot(xx.getRowVector(1), xx.getRowVector(2), new String[] {"x1-x2"});
51 canvas.setHolding(false);
52 Pause.pause();
53 gnuplot.close();
54 }
55 }
|