//TaggerFeature -- StanfordMaxEnt, A Maximum Entropy Toolkit
//Copyright (c) 2002-2008 Leland Stanford Junior University
//This program is free software; you can redistribute it and/or
//modify it under the terms of the GNU General Public License
//as published by the Free Software Foundation; either version 2
//of the License, or (at your option) any later version.
//This program is distributed in the hope that it will be useful,
//but WITHOUT ANY WARRANTY; without even the implied warranty of
//MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
//GNU General Public License for more details.
//You should have received a copy of the GNU General Public License
//along with this program; if not, write to the Free Software
//Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//For more information, bug reports, fixes, contact:
//Christopher Manning
//Dept of Computer Science, Gates 1A
//Stanford CA 94305-9010
//USA
// Support/Questions: java-nlp-user@lists.stanford.edu
// Licensing: java-nlp-support@lists.stanford.edu
//http://www-nlp.stanford.edu/software/tagger.shtml
package edu.stanford.nlp.tagger.maxent;
import edu.stanford.nlp.maxent.Feature;
/**
* Holds a Tagger Feature for the loglinear model.
* Tagger Features are binary valued, and indexed in a particular way.
*
* @author Kristina Toutanova
* @version 1.0
*/
public class TaggerFeature extends Feature {
private final int start;
private final int end;
private final FeatureKey key;
private final int yTag;
private final TaggerExperiments domain;
protected TaggerFeature(int start, int end, FeatureKey key,
int yTag, TaggerExperiments domain) {
this.start = start;
this.end = end;
this.key = key;
this.domain = domain;
this.yTag = yTag;
}
@Override
public double getVal(int index) {
return 1.0;
}
@Override
public int getY(int index) {
return yTag;
}
@Override
public int len() {
return end - start + 1;
}
@Override
public int getX(int index) {
return domain.getTaggerFeatures().xIndexed[start + index];
}
public int getYTag() {
return yTag;
}
@Override
public double getVal(int x, int y) {
int num = x * domain.ySize + y;
if (!(getYTag() == y)) {
return 0;
}
for (int i = 0; i < len(); i++) {
if (getX(i) == num) {
return 1;
}
}
return 0;
}
@Override
public double ftilde() {
double s = 0.0;
int y = getYTag();
for (int example = start; example < end + 1; example++) {
int x = domain.getTaggerFeatures().xIndexed[example];
s = s + domain.ptildeXY(x, y);
}
return s;
}
}