www.pudn.com > id3ClaafierTreeCode.rar > NodeLoss.java

package id3; 
import java.lang.*; 
import java.io.*; 
 
/** Class used for node accuracies. Stores the total weight of instances this node 
 * is responsible for, and also the total losses incurred by this node. 
 * 
 */ 
public class NodeLoss { 
    //added by JL 
     
    /** The total weight of instances in this node. 
     */ 
    public double totalWeight; 
    /** Total losses incurred by this node. 
     */ 
    public double totalLoss; 
    /** The totalLoss value squared. 
     */ 
    public double totalLossSquared; 
     
    private double UNDEFINED_REAL = -1.7976931348623157E+308; 
     
    /** Constructor. All values are set to the undefined value. 
     */ 
    NodeLoss(){ 
        totalWeight = UNDEFINED_REAL; 
        totalLoss = UNDEFINED_REAL; 
        totalLossSquared = UNDEFINED_REAL; 
    } 
     
    /** Display this NodeLoss object to a BufferedWriter. 
     * @param ostream The BufferedWriter to which this NodeLoss is displayed. 
     */ 
    public void display(BufferedWriter ostream) { 
        String output = new String(totalLoss + "/" + totalWeight + " (squared=" + totalLossSquared + ")"); 
        try{ostream.write(output,0,output.length());} 
        catch(Exception e){} 
    } 
     
    /** Updates the total weight and total loss information. 
     * @param weight The new total weight. 
     * @param loss The new loss value. 
     */ 
    public void update(double weight, double loss){ 
        totalWeight = totalWeight + weight; 
        totalLoss = totalLoss + (weight * loss); 
        totalLossSquared = totalLossSquared + (weight * loss * loss); 
    } 
}//End of NodeLoss class