import java.awt.*;
import java.awt.event.*;
import java.util.*;

// javac -target 1.1 CorrDimApplet.java

public class CorrDimApplet extends java.applet.Applet
    implements ActionListener {
    TextArea ta1, ta2;
    Button calculateButton, clearButton, testButton;

    static final double log10 = Math.log(10);
    static final int EMBED = 15;

    double[][] CorrDim(int mmax, int lag, int n, double[] x) {
        double[][] result = new double[mmax][101];
        for (int i = 0; i <= 100; i++)
            result[0][i] = 0.02 * i;
        normalize(n, x);
        double[] t1 = new double[mmax];
        double[] t2 = new double[mmax];
        for (int m = 2; m <= mmax; m++) {
            for (int i = 0; i < n - (m - 1) * lag - 1; i++) {
                for (int k = 0; k < m; k++) t1[k] = x[i + k * lag];
                for (int j = i + 1; j < n - (m - 1) * lag; j++) {
                    for (int k = 0; k < m; k++) t2[k] = x[j + k * lag];
                    double d = 100 * distance(m, t1, t2);
                    if (d < 0.1) d = 0.1;
                    int c = (int)(50 * Math.log(d) / log10 + 1);
                    if (c < 0) c = 0;
                    if (c <= 100) result[m-1][c]++;
                }
            }
            for (int c = 1; c <= 100; c++)
                result[m-1][c] += result[m-1][c-1];
            for (int c = 0; c <= 100; c++)
                if (result[m-1][c] == 0)
                    result[m-1][c] = -2;
                else
                    result[m-1][c] = Math.log(result[m-1][c]) / log10;
        }
        return result;
    }

    final double distance(int m, double[] p, double[] q) {
        double d = 0;
        for (int k = 0; k < m; k++)
            d += (p[k] - q[k]) * (p[k] - q[k]);
        return Math.sqrt(d / m);
    }

    void normalize(int n, double[] x) {
        double max = x[0];
        double min = x[0];
        for (int i = 1; i < n; i++)
            if (x[i] > max) max = x[i];
            else if (x[i] < min) min = x[i];
        for (int i = 0; i < n; i++)
            x[i] = (x[i] - min) / (max - min);
    }

    public void init() {
        setLayout(new BorderLayout());
        ta1 = new TextArea(10, 50);
        ta2 = new TextArea(10, 50);
        ta1.setEditable(true);
        ta2.setEditable(false);
        add("North", ta1);
        add("South", ta2);
        Panel pa = new Panel();
        add("Center", pa);
        calculateButton = new Button("Calculate");
        pa.add(calculateButton);
        calculateButton.addActionListener(this);
        clearButton = new Button("Clear");
        pa.add(clearButton);
        clearButton.addActionListener(this);
        testButton = new Button("Test (Henon)");
        pa.add(testButton);
        testButton.addActionListener(this);
    }

    static void henon(int n, double[] x) {
        double u = 0.3, v = 0.3;
        for (int i = 0; i < 100; i++) {
            double t = 1 - 1.4 * u * u + 0.3 * v;
            v = u;  u = t;
        }
        for (int i = 0; i < n; i++) {
            double t = 1 - 1.4 * u * u + 0.3 * v;
            v = u;  x[i] = u = t;
        }
    }

    void doit(int n, double[] x) {
        double[][] result = CorrDim(EMBED, 1, n, x);
        for (int i = 0; i <= 100; i++) {
            for (int m = 0; m < EMBED-1; m++)
                if (result[m][i] > -1)
                    ta2.append((float)result[m][i] + "\t");
                else
                    ta2.append("NA\t");
            if (result[EMBED-1][i] > -1)
                ta2.append((float)result[EMBED-1][i] + "\n");
            else
                ta2.append("NA\n");
        }
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == clearButton) {
            ta2.setText("");
        } else if (e.getSource() == calculateButton) {
            String s = ta1.getText();
            StringTokenizer t = new StringTokenizer(s);
            double[] x = new double[t.countTokens()];
            int n = 0;
            while (t.hasMoreTokens()) {
                try {
                    x[n++] = Double.valueOf(t.nextToken()).doubleValue();
                } catch (NumberFormatException ex) {
                }
            }
            ta2.append("n = " + n + "\n----------\n");
            doit(n, x);
        } else if (e.getSource() == testButton) {
            double[] x = new double[1000];
            henon(1000, x);
            for (int i = 0; i < 1000; i++)
                ta1.append(x[i] + "\n");
            ta2.append("n = " + 1000 + "\n----------\n");
            doit(1000, x);
        }
    }
}