made it start a graph, need to work on integrator

src/jat/examples/ThreeBodyExample/ThreeBodyAPL.java

@@ -1,12 +1,19 @@
 package jat.examples.ThreeBodyExample;
 
+import java.util.ArrayList;
+
 import org.apache.commons.math3.ode.FirstOrderDifferentialEquations;
+import org.apache.commons.math3.ode.sampling.StepHandler;
+import org.apache.commons.math3.ode.sampling.StepInterpolator;
 
 import jat.coreNOSA.cm.ThreeBody;
 import jat.coreNOSA.math.MatrixVector.data.VectorN;
 
 public class ThreeBodyAPL extends ThreeBody implements FirstOrderDifferentialEquations{
-
+	public ArrayList<Double> time = new ArrayList<Double>();
+	public ArrayList<Double> xsol = new ArrayList<Double>();
+	public ArrayList<Double> ysol = new ArrayList<Double>();
+	public ArrayList<Double> zsol = new ArrayList<Double>();
 	public ThreeBodyAPL(double G, double m1, double m2, double m3) {
 		super(G, m1, m2, m3);
 	}
@@ -20,7 +27,7 @@ public class ThreeBodyAPL extends ThreeBody implements FirstOrderDifferentialEqu
 	@Override
 	public int getDimension() {
 		// returns a dimension of 6
-		return 6;
+		return 18;
 	}
 	public double[] randv() {
 		double[] randv = new double[18];
@@ -44,4 +51,19 @@ public class ThreeBodyAPL extends ThreeBody implements FirstOrderDifferentialEqu
 		randv[17] = 8.0;
 		return randv;
 	}
+
+	public StepHandler stepHandler = new StepHandler() {
+		public void init(double t0, double[] y0, double t) {
+		}
+
+		public void handleStep(StepInterpolator interpolator, boolean isLast) {
+			double t = interpolator.getCurrentTime();
+			double[] y = interpolator.getInterpolatedState();
+			// System.out.println(t + " " + y[0] + " " + y[1]+ " " + y[2]);
+			time.add(t);
+			xsol.add(y[0]);
+			ysol.add(y[1]);
+			zsol.add(y[2]);
+		}
+	};
 }

src/jat/examples/ThreeBodyExample/ThreeBodyExample.java

@@ -20,23 +20,24 @@ import org.apache.commons.math3.ode.FirstOrderIntegrator;
 import org.apache.commons.math3.ode.nonstiff.DormandPrince853Integrator;
 
 public class ThreeBodyExample {
+
 	public ThreeBodyExample() {
 	}
-	
+
 	public static void main(String[] args) {
 		// Class that solves a three body problem and plots it
 		ThreeBodyExample x = new ThreeBodyExample();
-		
+
 		//initialize variables
 		double totalEnergy = 0;
 		// set the final time = one orbit period
-		double tf = 2.0;
-		
+		double tf = 7.0;
+
 		// create a ThreeBody orbit using three masses and gravitational con
 		ThreeBodyAPL sat = new ThreeBodyAPL(10, 0.3, 1.0, 2.0);
 		//initialize VectorN elements
 		double[] y = sat.randv();
-		
+
 		ArrayRealVector v = new ArrayRealVector(y);
 
 		DecimalFormat df2 = new DecimalFormat("#,###,###,##0.00");
@@ -45,27 +46,69 @@ public class ThreeBodyExample {
 
 		// find out the derivs of the problem
 		double[] derivs = sat.derivs(tf, y);
-		
+
 		// set the initial time to zero
 		double t0 = 0.0;
 		// obtain center of mass
 		VectorN cm = sat.center_of_mass(y);
-		
+
 		// obtain current energy
 		totalEnergy = sat.Energy(y);
-		
+
 		// propagate the orbit
-				//FirstOrderIntegrator dp853 = new DormandPrince853Integrator(1.0e-8, 100.0, 1.0e-10, 1.0e-10);
-				//dp853.addStepHandler(sat.stepHandler);
-				// double[] y = new double[] { 7000.0, 0, 0, .0, 8, 0 }; // initial
-				// state
-		//test outputs
+		FirstOrderIntegrator dp853 = new DormandPrince853Integrator(1.0e-8, 100.0, 1.0e-10, 1.0e-10);
+		dp853.addStepHandler(sat.stepHandler);
+		// double[] y = new double[] { 7000.0, 0, 0, .0, 8, 0 }; // initial
+		// state
+
+		dp853.integrate(sat, 0.0, y, 8000, y); // now y contains final state at
+		// tf
+
+		Double[] objArray = sat.time.toArray(new Double[sat.time.size()]);
+		double[] timeArray = ArrayUtils.toPrimitive(objArray);
+		double[] xsolArray = ArrayUtils.toPrimitive(sat.xsol.toArray(new Double[sat.time.size()]));
+		double[] ysolArray = ArrayUtils.toPrimitive(sat.ysol.toArray(new Double[sat.time.size()]));
+
+		double[][] XY = new double[timeArray.length][2];
+
+		// int a=0;
+		// System.arraycopy(timeArray,0,XY[a],0,timeArray.length);
+		// System.arraycopy(ysolArray,0,XY[1],0,ysolArray.length);
+
+		for (int i = 0; i < timeArray.length; i++) {
+			XY[i][0] = xsolArray[i];
+			XY[i][1] = ysolArray[i];
+		}
+
+		Plot2DPanel p = new Plot2DPanel();
+
+		// Plot2DPanel p = new Plot2DPanel(min, max, axesScales, axesLabels);
+
+		ScatterPlot s = new ScatterPlot("orbit", Color.RED, XY);
+		// LinePlot l = new LinePlot("sin", Color.RED, XY);
+		// l.closed_curve = false;
+		// l.draw_dot = true;
+		p.addPlot(s);
+		p.setLegendOrientation(PlotPanel.SOUTH);
+		double plotSize = 10000.;
+		double[] min = { -plotSize, -plotSize };
+		double[] max = { plotSize, plotSize };
+
+		p.setFixedBounds(min, max);
+		// test outputs
+		// output derivatives
 		for (int i = 0; i< derivs.length; i++)
 		{
 			System.out.println(derivs[i]);
 		}
+
+		// output center of mass
 		System.out.println(cm);
+
+		// output total energy of the system
 		System.out.println(totalEnergy);
-	}
+		new FrameView(p).setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
+		System.out.println("end");
+	}
 }