package edu.csusb.danby.stat; import java.awt.*; import javax.swing.*; import java.awt.event.*; import java.util.*; import java.text.NumberFormat; import java.awt.geom.*; import edu.csusb.danby.util.*; /** * This class is meant as a general purpose display for * regressions * @version Wed Jul 10 10:33:51 PDT 2002 */ public class RegressionPanel extends AxesPanel { /* Variables inherited from AxesPanel protected int panelWidth, panelHeight; // current panel width & height protected int graphWidth, graphHeight; protected Font f = new Font("Serif", Font.PLAIN,12); //font for labeling axes // viewport for graph, with default values protected double xRangeLow =-10.0; protected double xRangeHigh = 10.0; protected double yRangeLow =-10.0; protected double yRangeHigh = 10.0; METHODS INHERITED FROM AxesPanel protected int scaleX(double x) protected double inverseScaleX(double ix) protected int scaleY(double y) protected double inverseScaleY(double iy) */ private NumberFormat nf; protected Font titleFont = new Font("Serif", Font.PLAIN, 24); private double[] x,y; //vectors of data -- should be equal length private int dataLength; private RegressionCalculator rc; //class which does the calculations private double a,b; //regression coefficients //private double xRangeLow, xRangeHigh, yRangeLow, yRangeHigh; boolean showResidualLines; boolean showConfidenceBand=false; boolean showPredictionBand=false; private final static int CONFIDENCE =0; private final static int PREDICTION =1; // whether panel should choose own horizontal scale protected boolean autoscaleX=true; // whether panel should choose own vertical scale protected boolean autoscaleY = true; //critical values for t static double[] t005={Double.NaN, 63.657, 9.925, 5.841, 4.604, 4.032, 3.707, 3.499, 3.355, 3.250, 3.169, 3.106, 3.055, 3.012, 2.977, 2.947, 2.921, 2.898, 2.878,2.861, 2.845, 2.831, 2.819,2.807, 2.797, 2.787,2.779, 2.771, 2.763, 2.756, 2.756}; static double[] t025={Double.NaN, 12.706, 4.303, 3.182, 2.776, 2.571, 2.447, 2.365, 2.306, 2.262, 2.228, 2.201, 2.179, 2.160, 2.145, 2.131, 2.120, 2.110, 2.101, 2.093, 2.086, 2.080, 2.075, 2.069,2.064, 2.060, 2.056, 2.052, 2.048, 2.045, 1.960}; private double Sxx; public RegressionPanel( RegressionCalculator aRc) { super(); rc = aRc; this.setPreferredSize(new Dimension(300,400)); update(rc); nf = NumberFormat.getNumberInstance(); nf.setMaximumFractionDigits(3); if (autoscaleX && dataLength >0){ setXRange( rc.getMinX(), rc.getMaxX()); } if (autoscaleY && dataLength >0){ setYRange( rc.getMinY(), rc.getMaxY()); } } public void update(RegressionCalculator aRc) { rc = aRc; x = rc.getDataX(); y = rc.getDataY(); b = rc.getSlope(); a = rc.getIntercept(); dataLength = x.length; if ( autoscaleX && dataLength >0 ) { setXRange( minValue(x), maxValue(x)); } if (autoscaleY && dataLength > 0 ){ setYRange( minValue(y), maxValue(y)); } repaint(); } public void paint(Graphics g) { super.paint(g); int ix, iy; g.setColor(Color.black); for (int i=0; i< dataLength; i++){ ix = scaleX(x[i]); iy = scaleY(y[i]); g.fillOval(ix-3,iy-3,6,6); } if (showResidualLines){ g.setColor(Color.blue); g.drawLine(scaleX(xRangeLow), scaleY(yRangeLow), scaleX(xRangeHigh),scaleY(yRangeHigh)); } g.setColor(Color.red); if (dataLength >1){ g.drawLine(scaleX(xRangeLow), scaleY(b*xRangeLow+a), scaleX(xRangeHigh), scaleY(b*xRangeHigh+a)); } drawTitle(g); //MSE is sqrt(SSE/(n-2)), so don't try if n <=2 if (showConfidenceBand && (x.length>2)){ drawBand(g, CONFIDENCE); } if (showPredictionBand && (x.length>2)){ drawBand(g, PREDICTION); } } private double minValue(double[] data){ double min; if (data.length >0){ min = data[0]; //initial value for(int i=1; i< data.length; i++){ min =( data[i]0 ){ max = data[0]; //initial value for (int i=1; i< data.length; i++){ max = (data[i]>max)? data[i]: max; } return max; } else { return Double.NaN;} } private void drawBand(Graphics g, int type){ double n = x.length; double t; double S= Math.sqrt(rc.getMSE()); Graphics2D g2d = (Graphics2D)g; Sxx = rc.getSxx(); double xBar = rc.getXBar(); GeneralPath bandLimit = new GeneralPath(); if (x.length < 32){ t= t025[x.length-2];} else { t= t025[30];} //A is used in calculating sError //A is 0 for confidence intervals for means //A is 1 for prediction intervals double A; Color bandColor; if (type==CONFIDENCE){ A=0; bandColor = new Color(100,0,0); } else{//type=PREDICTION A=1; bandColor=new Color(0,0, 100); } double xs=xRangeLow; double ys = a+b*xs; double sError = S*Math.sqrt(A+1/n+(xs-xBar)*(xs-xBar)/Sxx); bandLimit.moveTo(scaleX(xs), scaleY(ys+t*sError)); double deltaX= (xRangeHigh-xRangeLow)/10.0; for (int i=1; i<= 10; i++){ xs=xs+deltaX; ys = a+b*xs; sError =S*Math.sqrt(A+1/n+(xs-xBar)*(xs-xBar)/Sxx); bandLimit.lineTo(scaleX(xs), scaleY(ys+t*sError)); } bandLimit.lineTo(scaleX(xs), scaleY(ys-t*sError)); for (int i=9; i >=0; i--){ xs = xs-deltaX; ys = a+b*xs; sError =S*Math.sqrt(A+1/n+(xs-xBar)*(xs-xBar)/Sxx); bandLimit.lineTo(scaleX(xs), scaleY(ys-t*sError)); } bandLimit.closePath(); g2d.setPaint(Color.gray); g2d.draw(bandLimit); g2d.setPaint(bandColor); Composite c= AlphaComposite.getInstance(AlphaComposite.SRC_OVER,.2f); g2d.setComposite(c); g2d.fill(bandLimit); } protected void drawTitle(Graphics g){ g.setFont(titleFont); g.setColor(Color.green); String title=new String("y = "+nf.format(a)+"+ "+nf.format(b)+"x"); //SHOULD USE FONT METRICS g.drawString(title,40,20); } public void setDrawConfidenceBand(boolean draw){ showConfidenceBand = draw; } public void setDrawPredictionBand(boolean draw){ showPredictionBand = draw; } public void doAutoscaleX(boolean as){ autoscaleX = as; } public void doAutoscaleY(boolean as){ autoscaleY=as; } }