featuretypessegmentlengthpoly2.java

来自「这是一个CRF(条件随机域)算法的实现,希望能对从事算法的有些帮助.」· Java 代码 · 共 59 行

/*
 * Created on Mar 23, 2005
 *
 */
package iitb.Model;

import iitb.CRF.DataSequence;

/**
 * @author sunita
 *
 */
public class FeatureTypesSegmentLengthPoly2 extends FeatureTypes {
    private static final long serialVersionUID = 220305L;
    float lenSq;
    short callNo;
    int maxSegLen;
    /**
     * @param fgen
     */
    public FeatureTypesSegmentLengthPoly2(FeatureGenImpl fgen, int maxSegLen) {
        super(fgen);
        this.maxSegLen = maxSegLen;
    }
    /* (non-Javadoc)
     * @see iitb.Model.FeatureTypes#startScanFeaturesAt(iitb.CRF.DataSequence, int, int)
     */
    public boolean startScanFeaturesAt(DataSequence data, int prevPos, int pos) {
        lenSq = (float)(pos-prevPos)/maxSegLen;
        callNo = 0;
        return true;
    }

    /* (non-Javadoc)
     * @see iitb.Model.FeatureTypes#hasNext()
     */
    public boolean hasNext() {
        return callNo < 2;
    }

    /* (non-Javadoc)
     * @see iitb.Model.FeatureTypes#next(iitb.Model.FeatureImpl)
     */
    public void next(FeatureImpl f) {
        String name;
        if (callNo == 0) {
            f.val = lenSq;
            f.strId.id = 0;
        } else {
            f.val = lenSq*lenSq;
            f.strId.id = 1;
        }
        if (featureCollectMode())
            f.strId.name = (f.strId.id==0)?"LENGTH^1":"LENGTH^2";
        callNo++;
    }

}