inequalitysplitter.java

Boosting算法软件包

package jboost.learner;

import jboost.examples.Attribute;
import jboost.examples.AttributeDescription;
import jboost.examples.Instance;
import jboost.examples.RealAttribute;

/**
 * Splits examples according to whether the value of a single
 * {@link jboost.examples.RealAttribute} is smaller than a fixed threshold.  
 */
class InequalitySplitter extends Splitter {
    private int index;
    private double threshold;

    public InequalitySplitter(int index, double threshold,AttributeDescription ad) {
	this.index = index;
	this.threshold = threshold;
	desc=ad;
	m_type= SplitterType.INEQUALITY_SPLITTER;
    }

    /** return a copy of this */
    public Object clone() {
	return new InequalitySplitter(index,threshold,desc);
    }

    public double getThreshold() {return threshold;}
    public int getIndex() {return index;}

    public String toString() {
	try{
	    return "InequalitySplitter. "+desc.getAttributeName()+
	    " < " + threshold;
	} catch(Exception e) {}
	return(null);
    }

   /** Returns a String containing Java code.				*/
    public String toJava(String fname) {
	return(null);
    }

   /** Returns a String containing C code.				*/
    public String toC(String fname) { return(null); }

   /** Get a summary.							*/
    public Summary getSummary() {
	Summary retval=new Summary();
	retval.index=index;
	retval.type=Summary.LESS_THAN;
	retval.val = new Double(threshold);
	return(retval);
    }

    public int eval(Instance instance) throws IncompAttException
    {
	Attribute t=instance.getAttribute(index);
	if(t == null) {return(-1);}
	try {
	    RealAttribute a= (RealAttribute) t;	// try downcasting 
	    return((a.getValue() > threshold)?1:0);
	}
	catch (ClassCastException e) {
	    throw new IncompAttException("InequalitySplitter Error:",index
					 ,t.getClass());
	}
    }
   
    public boolean equals(Splitter sp) {
	InequalitySplitter isp;
	try{isp=(InequalitySplitter)sp;}
	catch(ClassCastException e) {
		return(false);
	}
	if(index==isp.index && threshold==isp.threshold) return(true);
	else return(false);
    }
}