splitterbuilderworker.java

Boosting算法软件包

package jboost.atree;

import java.util.Vector;

import jboost.CandidateSplit;
import jboost.NotSupportedException;
import jboost.monitor.Monitor;
import jboost.util.BaseCountWorker;
import EDU.oswego.cs.dl.util.concurrent.CountDown;

/**
 * SplitterBuilderWorker is a Runnable worker class that
 * performs splitter building.
 *
 * @author Peter Kharchenko
 */
public class SplitterBuilderWorker extends BaseCountWorker {
    PredictorNodeSB pSB; 
    Vector splitters;
    
    public SplitterBuilderWorker(PredictorNodeSB pSB, Vector splitters, CountDown count) {
        super(count);
        this.pSB=pSB;
        this.splitters=splitters;
    }
    
    /**
     * Build a splitter using a single splitter buildier
     */
    protected void doWork() {
        CandidateSplit split;

        double trivLoss;
        long start;
        long stop;
      
        // create bag containing all m_examples reaching this node
        // tmpBag = m_booster.newBag(makeIndices((boolean []) m_masks.get(pSB.pNode)));
        // compute loss for trivial split
        // trivLoss = m_booster.getLoss(new Bag[] {tmpBag});
        // TODO: need to fix so that splits worse than trivial are not
        // added.  In the meantime, allow all splits.
        trivLoss= Double.MAX_VALUE;
        start= System.currentTimeMillis();
        int j=0;
        for (j= 0; j < pSB.SB.length; j++) {
            try {
                split= pSB.SB[j].build();
                
                // only add candidates with loss better than trivial split
                // TODO: figure out what to do if no splits better
                // than trivial
                if (split != null && split.getLoss() < trivLoss) {
                    splitters.add(new AtreeCandidateSplit(pSB.pNode, split));
                }
            } catch (NotSupportedException nse) {
                System.err.println(nse.getMessage());
                nse.printStackTrace();
            }
        }
        stop= System.currentTimeMillis();
        if (Monitor.logLevel > 3) {
            Monitor.log("It took an average of " + (stop-start)/(j*1000.0) + 
                    " seconds to build " + j + " splitterbuilders.");
        }     
    }
}