moa.streams.clustering.RandomRBFGeneratorEvents.java Source code

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/**
 * RandomRBFGeneratorEvents.java
 *
 * @author Richard Kirkby (rkirkby@cs.waikato.ac.nz) - RandomRBFGenerator 
 *          Timm Jansen (moa@cs.rwth-aachen.de) - Events
 * @editor Yunsu Kim
 * 
 * Last edited: 2013/06/02
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 *    
 *    
 */
package moa.streams.clustering;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.LinkedList;
import java.util.Random;
import java.util.Vector;

import moa.cluster.Clustering;
import moa.cluster.SphereCluster;
import moa.core.AutoExpandVector;
import moa.core.InstancesHeader;
import moa.core.ObjectRepository;
import moa.gui.visualization.DataPoint;
import moa.options.FlagOption;
import moa.options.FloatOption;
import moa.options.IntOption;
import moa.streams.InstanceStream;
import moa.tasks.TaskMonitor;
import weka.core.Attribute;
import weka.core.DenseInstance;
import weka.core.Instance;
import weka.core.Instances;

public class RandomRBFGeneratorEvents extends ClusteringStream {
    private transient Vector listeners;

    private static final long serialVersionUID = 1L;

    public IntOption modelRandomSeedOption = new IntOption("modelRandomSeed", 'm',
            "Seed for random generation of model.", 1);

    public IntOption instanceRandomSeedOption = new IntOption("instanceRandomSeed", 'i',
            "Seed for random generation of instances.", 5);

    public IntOption numClusterOption = new IntOption("numCluster", 'K',
            "The average number of centroids in the model.", 5, 1, Integer.MAX_VALUE);

    public IntOption numClusterRangeOption = new IntOption("numClusterRange", 'k',
            "Deviation of the number of centroids in the model.", 3, 0, Integer.MAX_VALUE);

    public FloatOption kernelRadiiOption = new FloatOption("kernelRadius", 'R',
            "The average radii of the centroids in the model.", 0.07, 0, 1);

    public FloatOption kernelRadiiRangeOption = new FloatOption("kernelRadiusRange", 'r',
            "Deviation of average radii of the centroids in the model.", 0, 0, 1);

    public FloatOption densityRangeOption = new FloatOption("densityRange", 'd',
            "Offset of the average weight a cluster has. Value of 0 means all cluster "
                    + "contain the same amount of points.",
            0, 0, 1);

    public IntOption speedOption = new IntOption("speed", 'V',
            "Kernels move a predefined distance of 0.01 every X points", 500, 1, Integer.MAX_VALUE);

    public IntOption speedRangeOption = new IntOption("speedRange", 'v', "Speed/Velocity point offset", 0, 0,
            Integer.MAX_VALUE);

    public FloatOption noiseLevelOption = new FloatOption("noiseLevel", 'N', "Noise level", 0.1, 0, 1);

    public FlagOption noiseInClusterOption = new FlagOption("noiseInCluster", 'n',
            "Allow noise to be placed within a cluster");

    public IntOption eventFrequencyOption = new IntOption("eventFrequency", 'E',
            "Event frequency. Enable at least one of the events below and set numClusterRange!", 30000, 0,
            Integer.MAX_VALUE);

    public FlagOption eventMergeSplitOption = new FlagOption("eventMergeSplitOption", 'M',
            "Enable merging and splitting of clusters. Set eventFrequency and numClusterRange!");

    public FlagOption eventDeleteCreateOption = new FlagOption("eventDeleteCreate", 'C',
            "Enable emering and disapperaing of clusters. Set eventFrequency and numClusterRange!");

    private double merge_threshold = 0.7;
    private int kernelMovePointFrequency = 10;
    private double maxDistanceMoveThresholdByStep = 0.01;
    private int maxOverlapFitRuns = 50;
    private double eventFrequencyRange = 0;

    private boolean debug = false;

    private AutoExpandVector<GeneratorCluster> kernels;
    protected Random instanceRandom;
    protected InstancesHeader streamHeader;
    private int numGeneratedInstances;
    private int numActiveKernels;
    private int nextEventCounter;
    private int nextEventChoice = -1;
    private int clusterIdCounter;
    private GeneratorCluster mergeClusterA;
    private GeneratorCluster mergeClusterB;
    private boolean mergeKernelsOverlapping = false;

    private class GeneratorCluster {
        //TODO: points is redundant to microclusterpoints, we need to come 
        //up with a good strategy that microclusters get updated and 
        //rebuild if needed. Idea: Sort microclusterpoints by timestamp and let 
        // microclusterdecay hold the timestamp for when the last point in a 
        //microcluster gets kicked, then we rebuild... or maybe not... could be
        //same as searching for point to be kicked. more likely is we rebuild 
        //fewer times then insert.

        SphereCluster generator;
        int kill = -1;
        boolean merging = false;
        double[] moveVector;
        int totalMovementSteps;
        int currentMovementSteps;
        boolean isSplitting = false;

        LinkedList<DataPoint> points = new LinkedList<DataPoint>();
        ArrayList<SphereCluster> microClusters = new ArrayList<SphereCluster>();
        ArrayList<ArrayList<DataPoint>> microClustersPoints = new ArrayList();
        ArrayList<Integer> microClustersDecay = new ArrayList();

        public GeneratorCluster(int label) {
            boolean outofbounds = true;
            int tryCounter = 0;
            while (outofbounds && tryCounter < maxOverlapFitRuns) {
                tryCounter++;
                outofbounds = false;
                double[] center = new double[numAttsOption.getValue()];
                double radius = kernelRadiiOption.getValue() + (instanceRandom.nextBoolean() ? -1 : 1)
                        * kernelRadiiRangeOption.getValue() * instanceRandom.nextDouble();
                while (radius <= 0) {
                    radius = kernelRadiiOption.getValue() + (instanceRandom.nextBoolean() ? -1 : 1)
                            * kernelRadiiRangeOption.getValue() * instanceRandom.nextDouble();
                }
                for (int j = 0; j < numAttsOption.getValue(); j++) {
                    center[j] = instanceRandom.nextDouble();
                    if (center[j] - radius < 0 || center[j] + radius > 1) {
                        outofbounds = true;
                        break;
                    }
                }
                generator = new SphereCluster(center, radius);
            }
            if (tryCounter < maxOverlapFitRuns) {
                generator.setId(label);
                double avgWeight = 1.0 / numClusterOption.getValue();
                double weight = avgWeight + (instanceRandom.nextBoolean() ? -1 : 1) * avgWeight
                        * densityRangeOption.getValue() * instanceRandom.nextDouble();
                generator.setWeight(weight);
                setDesitnation(null);
            } else {
                generator = null;
                kill = 0;
                System.out.println("Tried " + maxOverlapFitRuns + " times to create kernel. Reduce average radii.");
            }
        }

        public GeneratorCluster(int label, SphereCluster cluster) {
            this.generator = cluster;
            cluster.setId(label);
            setDesitnation(null);
        }

        public int getWorkID() {
            for (int c = 0; c < kernels.size(); c++) {
                if (kernels.get(c).equals(this))
                    return c;
            }
            return -1;
        }

        private void updateKernel() {
            if (kill == 0) {
                kernels.remove(this);
            }
            if (kill > 0) {
                kill--;
            }
            //we could be lot more precise if we would keep track of timestamps of points
            //then we could remove all old points and rebuild the cluster on up to date point base
            //BUT worse the effort??? so far we just want to avoid overlap with this, so its more
            //konservative as needed. Only needs to change when we need a thighter representation
            for (int m = 0; m < microClusters.size(); m++) {
                if (numGeneratedInstances - microClustersDecay.get(m) > decayHorizonOption.getValue()) {
                    microClusters.remove(m);
                    microClustersPoints.remove(m);
                    microClustersDecay.remove(m);
                }
            }

            if (!points.isEmpty()
                    && numGeneratedInstances - points.getFirst().getTimestamp() >= decayHorizonOption.getValue()) {
                //                if(debug)
                //                    System.out.println("Cleaning up macro cluster "+generator.getId());
                points.removeFirst();
            }

        }

        private void addInstance(Instance instance) {
            DataPoint point = new DataPoint(instance, numGeneratedInstances);
            points.add(point);

            int minMicroIndex = -1;
            double minHullDist = Double.MAX_VALUE;
            boolean inserted = false;
            //we favour more recently build clusters so we can remove earlier cluster sooner
            for (int m = microClusters.size() - 1; m >= 0; m--) {
                SphereCluster micro = microClusters.get(m);
                double hulldist = micro.getCenterDistance(point) - micro.getRadius();
                //point fits into existing cluster
                if (hulldist <= 0) {
                    microClustersPoints.get(m).add(point);
                    microClustersDecay.set(m, numGeneratedInstances);
                    inserted = true;
                    break;
                }
                //if not, check if its at least the closest cluster
                else {
                    if (hulldist < minHullDist) {
                        minMicroIndex = m;
                        minHullDist = hulldist;
                    }
                }
            }
            //Reseting index choice for alternative cluster building
            int alt = 1;
            if (alt == 1)
                minMicroIndex = -1;
            if (!inserted) {
                //add to closest cluster and expand cluster
                if (minMicroIndex != -1) {
                    microClustersPoints.get(minMicroIndex).add(point);
                    //we should keep the miniball instances and just check in
                    //new points instead of rebuilding the whole thing
                    SphereCluster s = new SphereCluster(microClustersPoints.get(minMicroIndex),
                            numAttsOption.getValue());
                    //check if current microcluster is bigger then generating cluster
                    if (s.getRadius() > generator.getRadius()) {
                        //remove previously added point
                        microClustersPoints.get(minMicroIndex)
                                .remove(microClustersPoints.get(minMicroIndex).size() - 1);
                        minMicroIndex = -1;
                    } else {
                        microClusters.set(minMicroIndex, s);
                        microClustersDecay.set(minMicroIndex, numGeneratedInstances);
                    }
                }
                //minMicroIndex might have been reset above
                //create new micro cluster
                if (minMicroIndex == -1) {
                    ArrayList<DataPoint> microPoints = new ArrayList<DataPoint>();
                    microPoints.add(point);
                    SphereCluster s;
                    if (alt == 0)
                        s = new SphereCluster(microPoints, numAttsOption.getValue());
                    else
                        s = new SphereCluster(generator.getCenter(), generator.getRadius(), 1);

                    microClusters.add(s);
                    microClustersPoints.add(microPoints);
                    microClustersDecay.add(numGeneratedInstances);
                    int id = 0;
                    while (id < kernels.size()) {
                        if (kernels.get(id) == this)
                            break;
                        id++;
                    }
                    s.setGroundTruth(id);
                }
            }

        }

        private void move() {
            if (currentMovementSteps < totalMovementSteps) {
                currentMovementSteps++;
                if (moveVector == null) {
                    return;
                } else {
                    double[] center = generator.getCenter();
                    boolean outofbounds = true;
                    while (outofbounds) {
                        double radius = generator.getRadius();
                        outofbounds = false;
                        center = generator.getCenter();
                        for (int d = 0; d < center.length; d++) {
                            center[d] += moveVector[d];
                            if (center[d] - radius < 0 || center[d] + radius > 1) {
                                outofbounds = true;
                                setDesitnation(null);
                                break;
                            }
                        }
                    }
                    generator.setCenter(center);
                }
            } else {
                if (!merging) {
                    setDesitnation(null);
                    isSplitting = false;
                }
            }
        }

        void setDesitnation(double[] destination) {

            if (destination == null) {
                destination = new double[numAttsOption.getValue()];
                for (int j = 0; j < numAttsOption.getValue(); j++) {
                    destination[j] = instanceRandom.nextDouble();
                }
            }
            double[] center = generator.getCenter();
            int dim = center.length;

            double[] v = new double[dim];

            for (int d = 0; d < dim; d++) {
                v[d] = destination[d] - center[d];
            }
            setMoveVector(v);
        }

        void setMoveVector(double[] vector) {
            //we are ignoring the steps, otherwise we have to change 
            //speed of the kernels, do we want that?
            moveVector = vector;
            int speedInPoints = speedOption.getValue();
            if (speedRangeOption.getValue() > 0)
                speedInPoints += (instanceRandom.nextBoolean() ? -1 : 1)
                        * instanceRandom.nextInt(speedRangeOption.getValue());
            if (speedInPoints < 1)
                speedInPoints = speedOption.getValue();

            double length = 0;
            for (int d = 0; d < moveVector.length; d++) {
                length += Math.pow(vector[d], 2);
            }
            length = Math.sqrt(length);

            totalMovementSteps = (int) (length / (maxDistanceMoveThresholdByStep * kernelMovePointFrequency)
                    * speedInPoints);
            for (int d = 0; d < moveVector.length; d++) {
                moveVector[d] /= (double) totalMovementSteps;
            }

            currentMovementSteps = 0;
            //            if(debug){
            //                System.out.println("Setting new direction for C"+generator.getId()+": distance "
            //                        +length+" in "+totalMovementSteps+" steps");
            //            }
        }

        private String tryMerging(GeneratorCluster merge) {
            String message = "";
            double overlapDegree = generator.overlapRadiusDegree(merge.generator);
            if (overlapDegree > merge_threshold) {
                SphereCluster mcluster = merge.generator;
                double radius = Math.max(generator.getRadius(), mcluster.getRadius());
                generator.combine(mcluster);

                //                //adjust radius, get bigger and bigger with high dim data
                generator.setRadius(radius);
                //                double[] center = generator.getCenter();
                //                double[] mcenter = mcluster.getCenter();
                //                double weight = generator.getWeight();
                //                double mweight = generator.getWeight();
                ////                for (int i = 0; i < center.length; i++) {
                ////                    center[i] = (center[i] * weight + mcenter[i] * mweight) / (mweight + weight);
                ////                }
                //                generator.setWeight(weight + mweight);
                message = "Clusters merging: " + mergeClusterB.generator.getId() + " into "
                        + mergeClusterA.generator.getId();

                //clean up and restet merging stuff
                //mark kernel so it gets killed when it doesn't contain any more instances
                merge.kill = decayHorizonOption.getValue();
                //set weight to 0 so no new instances will be created in the cluster
                mcluster.setWeight(0.0);
                normalizeWeights();
                numActiveKernels--;
                mergeClusterB = mergeClusterA = null;
                merging = false;
                mergeKernelsOverlapping = false;
            } else {
                if (overlapDegree > 0 && !mergeKernelsOverlapping) {
                    mergeKernelsOverlapping = true;
                    message = "Merge overlapping started";
                }
            }
            return message;
        }

        private String splitKernel() {
            isSplitting = true;
            //todo radius range
            double radius = kernelRadiiOption.getValue();
            double avgWeight = 1.0 / numClusterOption.getValue();
            double weight = avgWeight + avgWeight * densityRangeOption.getValue() * instanceRandom.nextDouble();
            SphereCluster spcluster = null;

            double[] center = generator.getCenter();
            spcluster = new SphereCluster(center, radius, weight);

            if (spcluster != null) {
                GeneratorCluster gc = new GeneratorCluster(clusterIdCounter++, spcluster);
                gc.isSplitting = true;
                kernels.add(gc);
                normalizeWeights();
                numActiveKernels++;
                return "Split from Kernel " + generator.getId();
            } else {
                System.out.println("Tried to split new kernel from C" + generator.getId()
                        + ". Not enough room for new cluster, decrease average radii, number of clusters or enable overlap.");
                return "";
            }
        }

        private String fadeOut() {
            kill = decayHorizonOption.getValue();
            generator.setWeight(0.0);
            numActiveKernels--;
            normalizeWeights();
            return "Fading out C" + generator.getId();
        }

    }

    public RandomRBFGeneratorEvents() {
        noiseInClusterOption.set();
        //        eventDeleteCreateOption.set();
        //        eventMergeSplitOption.set();
    }

    public InstancesHeader getHeader() {
        return streamHeader;
    }

    public long estimatedRemainingInstances() {
        return -1;
    }

    public boolean hasMoreInstances() {
        return true;
    }

    public boolean isRestartable() {
        return true;
    }

    @Override
    public void prepareForUseImpl(TaskMonitor monitor, ObjectRepository repository) {
        monitor.setCurrentActivity("Preparing random RBF...", -1.0);
        generateHeader();
        restart();
    }

    public void restart() {
        instanceRandom = new Random(instanceRandomSeedOption.getValue());
        nextEventCounter = eventFrequencyOption.getValue();
        nextEventChoice = getNextEvent();
        numActiveKernels = 0;
        numGeneratedInstances = 0;
        clusterIdCounter = 0;
        mergeClusterA = mergeClusterB = null;
        kernels = new AutoExpandVector<GeneratorCluster>();

        initKernels();
    }

    protected void generateHeader() { // 2013/06/02: Noise label
        ArrayList<Attribute> attributes = new ArrayList<Attribute>();
        for (int i = 0; i < this.numAttsOption.getValue(); i++) {
            attributes.add(new Attribute("att" + (i + 1)));
        }

        ArrayList<String> classLabels = new ArrayList<String>();
        for (int i = 0; i < this.numClusterOption.getValue(); i++) {
            classLabels.add("class" + (i + 1));
        }
        if (noiseLevelOption.getValue() > 0)
            classLabels.add("noise"); // The last label = "noise"

        attributes.add(new Attribute("class", classLabels));
        streamHeader = new InstancesHeader(
                new Instances(getCLICreationString(InstanceStream.class), attributes, 0));
        streamHeader.setClassIndex(streamHeader.numAttributes() - 1);
    }

    protected void initKernels() {
        for (int i = 0; i < numClusterOption.getValue(); i++) {
            kernels.add(new GeneratorCluster(clusterIdCounter));
            numActiveKernels++;
            clusterIdCounter++;
        }
        normalizeWeights();
    }

    public Instance nextInstance() {
        numGeneratedInstances++;
        eventScheduler();

        //make room for the classlabel
        double[] values_new = new double[numAttsOption.getValue() + 1];
        double[] values = null;
        int clusterChoice = -1;

        if (instanceRandom.nextDouble() > noiseLevelOption.getValue()) {
            clusterChoice = chooseWeightedElement();
            values = kernels.get(clusterChoice).generator.sample(instanceRandom).toDoubleArray();
        } else {
            //get ranodm noise point
            values = getNoisePoint();
        }

        if (Double.isNaN(values[0])) {
            System.out.println("Instance corrupted:" + numGeneratedInstances);
        }
        System.arraycopy(values, 0, values_new, 0, values.length);

        Instance inst = new DenseInstance(1.0, values_new);
        inst.setDataset(getHeader());
        if (clusterChoice == -1) {
            // 2013/06/02 (Yunsu Kim)
            // Noise instance has the last class value instead of "-1"
            // Preventing ArrayIndexOutOfBoundsException in WriteStreamToARFFFile
            inst.setClassValue(numClusterOption.getValue());
        } else {
            inst.setClassValue(kernels.get(clusterChoice).generator.getId());
            //Do we need micro cluster representation if have overlapping clusters?
            //if(!overlappingOption.isSet())
            kernels.get(clusterChoice).addInstance(inst);
        }
        //        System.out.println(numGeneratedInstances+": Overlap is"+updateOverlaps());

        return inst;
    }

    public Clustering getGeneratingClusters() {
        Clustering clustering = new Clustering();
        for (int c = 0; c < kernels.size(); c++) {
            clustering.add(kernels.get(c).generator);
        }
        return clustering;
    }

    public Clustering getMicroClustering() {
        Clustering clustering = new Clustering();
        int id = 0;

        for (int c = 0; c < kernels.size(); c++) {
            for (int m = 0; m < kernels.get(c).microClusters.size(); m++) {
                kernels.get(c).microClusters.get(m).setId(id);
                kernels.get(c).microClusters.get(m).setGroundTruth(kernels.get(c).generator.getId());
                clustering.add(kernels.get(c).microClusters.get(m));
                id++;
            }
        }

        //System.out.println("numMicroKernels "+clustering.size());
        return clustering;
    }

    /**************************** EVENTS ******************************************/
    private void eventScheduler() {

        for (int i = 0; i < kernels.size(); i++) {
            kernels.get(i).updateKernel();
        }

        nextEventCounter--;
        //only move kernels every 10 points, performance reasons????
        //should this be randomized as well???
        if (nextEventCounter % kernelMovePointFrequency == 0) {
            //move kernels
            for (int i = 0; i < kernels.size(); i++) {
                kernels.get(i).move();
                //overlapControl();
            }
        }

        if (eventFrequencyOption.getValue() == 0) {
            return;
        }

        String type = "";
        String message = "";
        boolean eventFinished = false;
        switch (nextEventChoice) {
        case 0:
            if (numActiveKernels > 1
                    && numActiveKernels > numClusterOption.getValue() - numClusterRangeOption.getValue()) {
                message = mergeKernels(nextEventCounter);
                type = "Merge";
            }
            if (mergeClusterA == null && mergeClusterB == null && message.startsWith("Clusters merging")) {
                eventFinished = true;
            }
            break;
        case 1:
            if (nextEventCounter <= 0) {
                if (numActiveKernels < numClusterOption.getValue() + numClusterRangeOption.getValue()) {
                    type = "Split";
                    message = splitKernel();
                }
                eventFinished = true;
            }
            break;
        case 2:
            if (nextEventCounter <= 0) {
                if (numActiveKernels > 1
                        && numActiveKernels > numClusterOption.getValue() - numClusterRangeOption.getValue()) {
                    message = fadeOut();
                    type = "Delete";
                }
                eventFinished = true;
            }
            break;
        case 3:
            if (nextEventCounter <= 0) {
                if (numActiveKernels < numClusterOption.getValue() + numClusterRangeOption.getValue()) {
                    message = fadeIn();
                    type = "Create";
                }
                eventFinished = true;
            }
            break;

        }
        if (eventFinished) {
            nextEventCounter = (int) (eventFrequencyOption.getValue() + (instanceRandom.nextBoolean() ? -1 : 1)
                    * eventFrequencyOption.getValue() * eventFrequencyRange * instanceRandom.nextDouble());
            nextEventChoice = getNextEvent();
            //System.out.println("Next event choice: "+nextEventChoice);
        }
        if (!message.isEmpty()) {
            message += " (numKernels = " + numActiveKernels + " at " + numGeneratedInstances + ")";
            if (!type.equals("Merge") || message.startsWith("Clusters merging"))
                fireClusterChange(numGeneratedInstances, type, message);
        }
    }

    private int getNextEvent() {
        int choice = -1;
        boolean lowerLimit = numActiveKernels <= numClusterOption.getValue() - numClusterRangeOption.getValue();
        boolean upperLimit = numActiveKernels >= numClusterOption.getValue() + numClusterRangeOption.getValue();

        if (!lowerLimit || !upperLimit) {
            int mode = -1;
            if (eventDeleteCreateOption.isSet() && eventMergeSplitOption.isSet()) {
                mode = instanceRandom.nextInt(2);
            }

            if (mode == 0 || (mode == -1 && eventMergeSplitOption.isSet())) {
                //have we reached a limit? if not free choice
                if (!lowerLimit && !upperLimit)
                    choice = instanceRandom.nextInt(2);
                else
                //we have a limit. if lower limit, choose split
                if (lowerLimit)
                    choice = 1;
                //otherwise we reached upper level, choose merge
                else
                    choice = 0;
            }

            if (mode == 1 || (mode == -1 && eventDeleteCreateOption.isSet())) {
                //have we reached a limit? if not free choice
                if (!lowerLimit && !upperLimit)
                    choice = instanceRandom.nextInt(2) + 2;
                else
                //we have a limit. if lower limit, choose create
                if (lowerLimit)
                    choice = 3;
                //otherwise we reached upper level, choose delete
                else
                    choice = 2;
            }
        }

        return choice;
    }

    private String fadeOut() {
        int id = instanceRandom.nextInt(kernels.size());
        while (kernels.get(id).kill != -1)
            id = instanceRandom.nextInt(kernels.size());

        String message = kernels.get(id).fadeOut();
        return message;
    }

    private String fadeIn() {
        GeneratorCluster gc = new GeneratorCluster(clusterIdCounter++);
        kernels.add(gc);
        numActiveKernels++;
        normalizeWeights();
        return "Creating new cluster";
    }

    private String changeWeight(boolean increase) {
        double changeRate = 0.1;
        int id = instanceRandom.nextInt(kernels.size());
        while (kernels.get(id).kill != -1)
            id = instanceRandom.nextInt(kernels.size());

        int sign = 1;
        if (!increase)
            sign = -1;
        double weight_old = kernels.get(id).generator.getWeight();
        double delta = sign * numActiveKernels * instanceRandom.nextDouble() * changeRate;
        kernels.get(id).generator.setWeight(weight_old + delta);

        normalizeWeights();

        String message;
        if (increase)
            message = "Increase ";
        else
            message = "Decrease ";
        message += " weight on Cluster " + id + " from " + weight_old + " to " + (weight_old + delta);
        return message;

    }

    private String changeRadius(boolean increase) {
        double maxChangeRate = 0.1;
        int id = instanceRandom.nextInt(kernels.size());
        while (kernels.get(id).kill != -1)
            id = instanceRandom.nextInt(kernels.size());

        int sign = 1;
        if (!increase)
            sign = -1;

        double r_old = kernels.get(id).generator.getRadius();
        double r_new = r_old + sign * r_old * instanceRandom.nextDouble() * maxChangeRate;
        if (r_new >= 0.5)
            return "Radius to big";
        kernels.get(id).generator.setRadius(r_new);

        String message;
        if (increase)
            message = "Increase ";
        else
            message = "Decrease ";
        message += " radius on Cluster " + id + " from " + r_old + " to " + r_new;
        return message;
    }

    private String splitKernel() {
        int id = instanceRandom.nextInt(kernels.size());
        while (kernels.get(id).kill != -1)
            id = instanceRandom.nextInt(kernels.size());

        String message = kernels.get(id).splitKernel();

        return message;
    }

    private String mergeKernels(int steps) {
        if (numActiveKernels > 1 && ((mergeClusterA == null && mergeClusterB == null))) {

            //choose clusters to merge
            double diseredDist = steps / speedOption.getValue() * maxDistanceMoveThresholdByStep;
            double minDist = Double.MAX_VALUE;
            //           System.out.println("DisredDist:"+(2*diseredDist));
            for (int i = 0; i < kernels.size(); i++) {
                for (int j = 0; j < i; j++) {
                    if (kernels.get(i).kill != -1 || kernels.get(j).kill != -1) {
                        continue;
                    } else {
                        double kernelDist = kernels.get(i).generator.getCenterDistance(kernels.get(j).generator);
                        double d = kernelDist - 2 * diseredDist;
                        //                     System.out.println("Dist:"+i+" / "+j+" "+d);
                        if (Math.abs(d) < minDist
                                && (minDist != Double.MAX_VALUE || d > 0 || Math.abs(d) < 0.001)) {
                            minDist = Math.abs(d);
                            mergeClusterA = kernels.get(i);
                            mergeClusterB = kernels.get(j);
                        }
                    }
                }
            }

            if (mergeClusterA != null && mergeClusterB != null) {
                double[] merge_point = mergeClusterA.generator.getCenter();
                double[] v = mergeClusterA.generator.getDistanceVector(mergeClusterB.generator);
                for (int i = 0; i < v.length; i++) {
                    merge_point[i] = merge_point[i] + v[i] * 0.5;
                }

                mergeClusterA.merging = true;
                mergeClusterB.merging = true;
                mergeClusterA.setDesitnation(merge_point);
                mergeClusterB.setDesitnation(merge_point);

                if (debug) {
                    System.out.println("Center1" + Arrays.toString(mergeClusterA.generator.getCenter()));
                    System.out.println("Center2" + Arrays.toString(mergeClusterB.generator.getCenter()));
                    System.out.println("Vector" + Arrays.toString(v));

                    System.out.println("Try to merge cluster " + mergeClusterA.generator.getId() + " into "
                            + mergeClusterB.generator.getId() + " at " + Arrays.toString(merge_point) + " time "
                            + numGeneratedInstances);
                }
                return "Init merge";
            }
        }

        if (mergeClusterA != null && mergeClusterB != null) {

            //movekernels will move the kernels close to each other,
            //we just need to check and merge here if they are close enough
            return mergeClusterA.tryMerging(mergeClusterB);
        }

        return "";
    }

    /************************* TOOLS **************************************/

    public void getDescription(StringBuilder sb, int indent) {

    }

    private double[] getNoisePoint() {
        double[] sample = new double[numAttsOption.getValue()];
        boolean incluster = true;
        int counter = 20;
        while (incluster) {
            for (int j = 0; j < numAttsOption.getValue(); j++) {
                sample[j] = instanceRandom.nextDouble();
            }
            incluster = false;
            if (!noiseInClusterOption.isSet() && counter > 0) {
                counter--;
                for (int c = 0; c < kernels.size(); c++) {
                    for (int m = 0; m < kernels.get(c).microClusters.size(); m++) {
                        Instance inst = new DenseInstance(1, sample);
                        if (kernels.get(c).microClusters.get(m).getInclusionProbability(inst) > 0) {
                            incluster = true;
                            break;
                        }
                    }
                    if (incluster)
                        break;
                }
            }
        }

        //        double [] sample = new double [numAttsOption.getValue()];
        //        for (int j = 0; j < numAttsOption.getValue(); j++) {
        //             sample[j] = instanceRandom.nextDouble();
        //        }

        return sample;
    }

    private int chooseWeightedElement() {
        double r = instanceRandom.nextDouble();

        // Determine index of choosen element
        int i = 0;
        while (r > 0.0) {
            r -= kernels.get(i).generator.getWeight();
            i++;
        }
        --i; // Overcounted once
        //System.out.println(i);
        return i;
    }

    private void normalizeWeights() {
        double sumWeights = 0.0;
        for (int i = 0; i < kernels.size(); i++) {
            sumWeights += kernels.get(i).generator.getWeight();
        }
        for (int i = 0; i < kernels.size(); i++) {
            kernels.get(i).generator.setWeight(kernels.get(i).generator.getWeight() / sumWeights);
        }
    }

    /*************** EVENT Listener *********************/
    // should go into the superclass of the generator, create new one for cluster streams?

    /** Add a listener */
    synchronized public void addClusterChangeListener(ClusterEventListener l) {
        if (listeners == null)
            listeners = new Vector();
        listeners.addElement(l);
    }

    /** Remove a listener */
    synchronized public void removeClusterChangeListener(ClusterEventListener l) {
        if (listeners == null)
            listeners = new Vector();
        listeners.removeElement(l);
    }

    /** Fire a ClusterChangeEvent to all registered listeners */
    protected void fireClusterChange(long timestamp, String type, String message) {
        // if we have no listeners, do nothing...
        if (listeners != null && !listeners.isEmpty()) {
            // create the event object to send
            ClusterEvent event = new ClusterEvent(this, timestamp, type, message);

            // make a copy of the listener list in case
            //   anyone adds/removes listeners
            Vector targets;
            synchronized (this) {
                targets = (Vector) listeners.clone();
            }

            // walk through the listener list and
            //   call the sunMoved method in each
            Enumeration e = targets.elements();
            while (e.hasMoreElements()) {
                ClusterEventListener l = (ClusterEventListener) e.nextElement();
                l.changeCluster(event);

            }
        }
    }

    @Override
    public String getPurposeString() {
        return "Generates a random radial basis function stream.";
    }

    public String getParameterString() {
        return "";
    }

}