source: trunk/CrossPare/src/de/ugoe/cs/cpdp/training/WekaClusterTraining2.java @ 4

package de.ugoe.cs.cpdp.training;

import java.io.PrintStream;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import java.util.logging.Level;

import org.apache.commons.io.output.NullOutputStream;

import de.ugoe.cs.util.console.Console;
import weka.classifiers.AbstractClassifier;
import weka.classifiers.Classifier;
import weka.clusterers.EM;
import weka.core.DenseInstance;
import weka.core.Instance;
import weka.core.Instances;
import weka.filters.Filter;
import weka.filters.unsupervised.attribute.Remove;

/**
 * WekaClusterTraining2
 * 
 * 1. Cluster traindata
 * 2. for each cluster train a classifier with traindata from cluster
 * 3. match testdata instance to a cluster, then classify with classifier from the cluster
 * 
 * XML config:
 * <!-- because of clustering -->
 * <preprocessor name="Normalization" param=""/>
 * 
 * <!-- cluster trainer -->
 * <trainer name="WekaClusterTraining2" param="NaiveBayes weka.classifiers.bayes.NaiveBayes" />
 * 
 * Questions:
 * - how do we configure the clustering params?
 */
public class WekaClusterTraining2 extends WekaBaseTraining2 implements ITrainingStrategy {

        private final TraindatasetCluster classifier = new TraindatasetCluster();
        
        @Override
        public Classifier getClassifier() {
                return classifier;
        }
        
        
        @Override
        public void apply(Instances traindata) {
                PrintStream errStr      = System.err;
                System.setErr(new PrintStream(new NullOutputStream()));
                try {
                        classifier.buildClassifier(traindata);
                } catch (Exception e) {
                        throw new RuntimeException(e);
                } finally {
                        System.setErr(errStr);
                }
        }
        

        public class TraindatasetCluster extends AbstractClassifier {
                
                private static final long serialVersionUID = 1L;

                private EM clusterer = null;

                private HashMap<Integer, Classifier> cclassifier = new HashMap<Integer, Classifier>();
                private HashMap<Integer, Instances> ctraindata = new HashMap<Integer, Instances>(); 
                
                
                
                private Instance createInstance(Instances instances, Instance instance) {
                        // attributes for feeding instance to classifier
                        Set<String> attributeNames = new HashSet<>();
                        for( int j=0; j<instances.numAttributes(); j++ ) {
                                attributeNames.add(instances.attribute(j).name());
                        }
                        
                        double[] values = new double[instances.numAttributes()];
                        int index = 0;
                        for( int j=0; j<instance.numAttributes(); j++ ) {
                                if( attributeNames.contains(instance.attribute(j).name())) {
                                        values[index] = instance.value(j);
                                        index++;
                                }
                        }
                        
                        Instances tmp = new Instances(instances);
                        tmp.clear();
                        Instance instCopy = new DenseInstance(instance.weight(), values);
                        instCopy.setDataset(tmp);
                        
                        return instCopy;
                }
                
                
                @Override
                public double classifyInstance(Instance instance) {
                        double ret = 0;
                        try {
                                Instances traindata = ctraindata.get(0);
                                Instance classInstance = createInstance(traindata, instance);
                                
                                // remove class attribute before clustering
                                Remove filter = new Remove();
                                filter.setAttributeIndices("" + (traindata.classIndex() + 1));
                                filter.setInputFormat(traindata);
                                traindata = Filter.useFilter(traindata, filter);
                                
                                Instance clusterInstance = createInstance(traindata, instance);
                                
                                // 1. classify testdata instance to a cluster number
                                int cnum = clusterer.clusterInstance(clusterInstance);
                                
                                // 2. classify testata instance to the classifier
                                ret = cclassifier.get(cnum).classifyInstance(classInstance);
                                
                        }catch( Exception e ) {
                                Console.traceln(Level.INFO, String.format("ERROR matching instance to cluster!"));
                                throw new RuntimeException(e);
                        }
                        return ret;
                }

                
                
                @Override
                public void buildClassifier(Instances traindata) throws Exception {
                        
                        // 1. copy traindata
                        Instances train = new Instances(traindata);
                        
                        // 2. remove class attribute for clustering
                        Remove filter = new Remove();
                        filter.setAttributeIndices("" + (train.classIndex() + 1));
                        filter.setInputFormat(train);
                        train = Filter.useFilter(train, filter);
                        
                        // 3. cluster data
                        //Console.traceln(Level.INFO, String.format("starting clustering"));
                        
                        // use standard params for now
                        clusterer = new EM();
                        //String[] params = {"-N", "100"};
                        //clusterer.setOptions(params);
                        clusterer.buildClusterer(train);
                        // set max num to traindata size
                        clusterer.setMaximumNumberOfClusters(train.size());
                        
                        // 4. get cluster membership of our traindata
                        //AddCluster cfilter = new AddCluster();
                        //cfilter.setClusterer(clusterer);
                        //cfilter.setInputFormat(train);
                        //Instances ctrain = Filter.useFilter(train, cfilter);
                        
                        Instances ctrain = new Instances(train);
                        
                        // get traindata per cluster
                        int cnumber;
                        for ( int j=0; j < ctrain.numInstances(); j++ ) {
                                // get the cluster number from the attributes, subract 1 because if we clusterInstance we get 0-n, and this is 1-n
                                //cnumber = Integer.parseInt(ctrain.get(j).stringValue(ctrain.get(j).numAttributes()-1).replace("cluster", "")) - 1;
                                
                                cnumber = clusterer.clusterInstance(ctrain.get(j));
                                // add training data to list of instances for this cluster number
                                if ( !ctraindata.containsKey(cnumber) ) {
                                        ctraindata.put(cnumber, new Instances(traindata));
                                        ctraindata.get(cnumber).delete();
                                }
                                ctraindata.get(cnumber).add(traindata.get(j));
                        }
                        
                        // train one classifier per cluster, we get the clusternumber from the traindata
                        Iterator<Integer> clusternumber = ctraindata.keySet().iterator();
                        while ( clusternumber.hasNext() ) {
                                cnumber = clusternumber.next();                 
                                cclassifier.put(cnumber,setupClassifier());
                                cclassifier.get(cnumber).buildClassifier(ctraindata.get(cnumber));
                                
                                //Console.traceln(Level.INFO, String.format("classifier in cluster "+cnumber));
                        }
                }
        }
}