audio.cords.old.RegressionDemo.java Source code

Introduction

Here is the source code for audio.cords.old.RegressionDemo.java

Source

package audio.cords.old;

/*
 * Simple Linear Regression Demo
 * Created by Tim De Pauw <http://pwnt.be/> on 2009-08-17
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

import java.awt.Paint;
import java.util.Random;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.DrawingSupplier;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.StandardXYItemRenderer;
import org.jfree.chart.renderer.xy.XYItemRenderer;
import org.jfree.data.xy.XYDataset;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
import org.jfree.ui.ApplicationFrame;
import org.jfree.ui.RefineryUtilities;

@SuppressWarnings("serial")
public class RegressionDemo extends ApplicationFrame {
    public RegressionDemo(XYSeriesCollection data) {
        super("Regression Demo");
        setContentPane(new ChartPanel(createChart(data)));
        pack();
    }

    private static JFreeChart createChart(XYSeriesCollection data) {
        JFreeChart chart = ChartFactory.createScatterPlot(null, "X", "Y", data, PlotOrientation.VERTICAL, true,
                false, false);
        XYPlot plot = (XYPlot) chart.getPlot();
        XYItemRenderer scatterRenderer = plot.getRenderer();
        StandardXYItemRenderer regressionRenderer = new StandardXYItemRenderer();
        regressionRenderer.setBaseSeriesVisibleInLegend(false);
        plot.setDataset(1, regress(data));
        plot.setRenderer(1, regressionRenderer);
        DrawingSupplier ds = plot.getDrawingSupplier();
        for (int i = 0; i < data.getSeriesCount(); i++) {
            Paint paint = ds.getNextPaint();
            scatterRenderer.setSeriesPaint(i, paint);
            regressionRenderer.setSeriesPaint(i, paint);
        }
        return chart;
    }

    private static XYDataset regress(XYSeriesCollection data) {
        // Determine bounds
        double xMin = Double.MAX_VALUE, xMax = 0;
        for (int i = 0; i < data.getSeriesCount(); i++) {
            XYSeries ser = data.getSeries(i);
            for (int j = 0; j < ser.getItemCount(); j++) {
                double x = ser.getX(j).doubleValue();
                if (x < xMin) {
                    xMin = x;
                }
                if (x > xMax) {
                    xMax = x;
                }
            }
        }
        // Create 2-point series for each of the original series
        XYSeriesCollection coll = new XYSeriesCollection();
        for (int i = 0; i < data.getSeriesCount(); i++) {
            XYSeries ser = data.getSeries(i);
            int n = ser.getItemCount();
            double sx = 0, sy = 0, sxx = 0, sxy = 0, syy = 0;
            for (int j = 0; j < n; j++) {
                double x = ser.getX(j).doubleValue();
                double y = ser.getY(j).doubleValue();
                sx += x;
                sy += y;
                sxx += x * x;
                sxy += x * y;
                syy += y * y;
            }
            double b = (n * sxy - sx * sy) / (n * sxx - sx * sx);
            double a = sy / n - b * sx / n;
            XYSeries regr = new XYSeries(ser.getKey());
            regr.add(xMin, a + b * xMin);
            regr.add(xMax, a + b * xMax);
            coll.addSeries(regr);
        }
        return coll;
    }

    private static XYSeriesCollection getTestData() {
        Random rg = new Random();
        XYSeriesCollection data = new XYSeriesCollection();
        for (int i = 1; i <= 3; i++) {
            XYSeries series = new XYSeries("Series " + i);
            double a = rg.nextDouble() - .5;
            int b = rg.nextInt(20) - 10;
            for (int j = 1; j <= 20; j++) {
                double x = j + (rg.nextDouble() - .5);
                double y = a * j + b + (rg.nextDouble() - .5) * 2;
                series.add(x, y);
            }
            data.addSeries(series);
        }
        return data;
    }

    public static void main(String[] args) throws Exception {
        RegressionDemo demo = new RegressionDemo(getTestData());
        RefineryUtilities.centerFrameOnScreen(demo);
        demo.setVisible(true);
    }
}