/*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* LabelPowersetTransformation.java
* Copyright (C) 2009-2010 Aristotle University of Thessaloniki, Thessaloniki, Greece
*/
package mulan.transformations;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashSet;
import mulan.data.LabelSet;
import mulan.data.MultiLabelInstances;
import weka.core.Attribute;
import weka.core.Instance;
import weka.core.Instances;
/**
* Class that implement the Label powerset (LP) transformation method
*
* @author Stavros Mpakirtzoglou
* @author Grigorios Tsoumakas
*/
public class LabelPowersetTransformation implements Serializable {
private Instances transformedFormat;
public Instances getTransformedFormat() {
return transformedFormat;
}
public Instances transformInstances(MultiLabelInstances mlData) throws Exception {
Instances data = mlData.getDataSet();
int numLabels = mlData.getNumLabels();
int[] labelIndices = mlData.getLabelIndices();
Instances newData = null;
// gather distinct label combinations
HashSet<LabelSet> labelSets = new HashSet<LabelSet>();
int numInstances = data.numInstances();
for (int i = 0; i < numInstances; i++) {
// construct labelset
double[] dblLabels = new double[numLabels];
for (int j = 0; j < numLabels; j++) {
int index = labelIndices[j];
dblLabels[j] = Double.parseDouble(data.attribute(index).value((int) data.instance(i).value(index)));
}
LabelSet labelSet = new LabelSet(dblLabels);
// add labelset if not already present
labelSets.add(labelSet);
}
// create class attribute
ArrayList<String> classValues = new ArrayList<String>(labelSets.size());
for (LabelSet subset : labelSets) {
classValues.add(subset.toBitString());
}
Attribute newClass = new Attribute("class", classValues);
// remove all labels
newData = RemoveAllLabels.transformInstances(data, labelIndices);
// add new class attribute
newData.insertAttributeAt(newClass, newData.numAttributes());
newData.setClassIndex(newData.numAttributes() - 1);
// add class values
for (int i = 0; i < newData.numInstances(); i++) {
//System.out.println(newData.instance(i).toString());
String strClass = "";
for (int j = 0; j < numLabels; j++) {
int index = labelIndices[j];
strClass = strClass + data.attribute(index).value((int) data.instance(i).value(index));
}
//System.out.println(strClass);
newData.instance(i).setClassValue(strClass);
}
transformedFormat = new Instances(newData, 0);
return newData;
}
public Instance transformInstance(Instance instance, int[] labelIndices) throws Exception {
Instance transformedInstance = RemoveAllLabels.transformInstance(instance, labelIndices);
transformedInstance.setDataset(null);
transformedInstance.insertAttributeAt(transformedInstance.numAttributes());
transformedInstance.setDataset(transformedFormat);
return transformedInstance;
}
}