Point.java

package tr.gov.ulakbim.jDenetX.clusterers.streamkm;

import tr.gov.ulakbim.jDenetX.cluster.Cluster;
import tr.gov.ulakbim.jDenetX.cluster.SphereCluster;
import weka.core.Instance;

/**
 * @author Marcel R. Ackermann, Christiane Lammersen, Marcus Maertens, Christoph Raupach,
 *         Christian Sohler, Kamil Swierkot
 */

public class Point {

    //dimension
    int dimension;

    //Clustering Features (weight, squareSum, linearSum)
    double weight;
    double squareSum;
    double[] coordinates;

    //cost and index of the centre, the point is currently assigned to
    double curCost;
    int centreIndex;

    //id and class (if there is class information in the file)
    int id;
    int cl;

    public Point(int dimension) {
        this.weight = 1.0;
        this.squareSum = 0.0;
        this.dimension = dimension;
        this.coordinates = new double[dimension];
        this.id = -1;
        this.cl = -1;
        this.curCost = 0;
        this.centreIndex = -1;
        for (int l = 0; l < dimension; l++) {
            this.coordinates[l] = 0.0;
        }
    }

    public Point(Instance inst, int id) {
        this.weight = inst.weight();
        this.squareSum = 0.0;
        this.dimension = inst.numAttributes();
        this.coordinates = new double[this.dimension];
        this.id = id;
        this.cl = 0;// NOT USED (int) inst.classValue();
        this.curCost = 0;
        this.centreIndex = -1;
        for (int l = 0; l < this.dimension; l++) {
            double nextNumber = inst.value(l) * inst.value(l);
            this.coordinates[l] = inst.value(l);
            this.squareSum += nextNumber * nextNumber;
        }
    }

    public Point clone() {
        Point res = new Point(this.dimension);
        res.weight = this.weight;
        res.squareSum = this.squareSum;
        res.dimension = this.dimension;
        res.coordinates = this.coordinates.clone();
        res.id = this.id;
        res.cl = this.cl;
        res.curCost = this.curCost;
        res.centreIndex = this.centreIndex;
        return res;
    }

    public Cluster toCluster() {
        //Convert point to Cluster
        return (new SphereCluster(this.coordinates, .05, this.weight)); //Radius = .05?

    }

    /**
     * Computes the cost of this point with the given array of centres centres[] (of size k)
     */
    public double costOfPoint(int k, Point[] centres) {
        double nearestCost = -1.0;
        for (int j = 0; j < k; j++) {
            double distance = 0.0;
            int l = 0;
            for (l = 0; l < this.dimension; l++) {
                //Centroid coordinate of the point
                double centroidCoordinatePoint;
                if (this.weight != 0.0) {
                    centroidCoordinatePoint = this.coordinates[l] / this.weight;
                } else {
                    centroidCoordinatePoint = this.coordinates[l];
                }
                //Centroid coordinate of the centre
                double centroidCoordinateCentre;
                if (centres[j].weight != 0.0) {
                    centroidCoordinateCentre = centres[j].coordinates[l] / centres[j].weight;
                } else {
                    centroidCoordinateCentre = centres[j].coordinates[l];
                }
                distance += (centroidCoordinatePoint - centroidCoordinateCentre) *
                        (centroidCoordinatePoint - centroidCoordinateCentre);
            }

            if (nearestCost < 0 || distance < nearestCost) {
                nearestCost = distance;
            }
        }
        return this.weight * nearestCost;
    }


    /**
     * Computes the index of the centre nearest to this point with the given array of centres centres[] (of size k)
     */
    public int determineClusterCentreKMeans(int k, Point[] centres) {
        int centre = 0;
        double nearestCost = -1.0;
        for (int j = 0; j < k; j++) {
            double distance = 0.0;
            for (int l = 0; l < this.dimension; l++) {
                //Centroid coordinate of the point
                double centroidCoordinatePoint;
                if (this.weight != 0.0) {
                    centroidCoordinatePoint = this.coordinates[l] / this.weight;
                } else {
                    centroidCoordinatePoint = this.coordinates[l];
                }
                //Centroid coordinate of the centre
                double centroidCoordinateCentre;
                if (centres[j].weight != 0.0) {
                    centroidCoordinateCentre = centres[j].coordinates[l] / centres[j].weight;
                } else {
                    centroidCoordinateCentre = centres[j].coordinates[l];
                }
                distance += (centroidCoordinatePoint - centroidCoordinateCentre) *
                        (centroidCoordinatePoint - centroidCoordinateCentre);
            }

            if (nearestCost < 0 || distance < nearestCost) {
                nearestCost = distance;
                centre = j;
            }
        }
        return centre;
    }


    /**
     * Computes the cost of this point with centre centre
     */
    public double costOfPointToCenter(Point centre) {
        if (this.weight == 0.0) {
            return 0.0;
        }

        //stores the distance between p and centre
        double distance = 0.0;

        //loop counter
        for (int l = 0; l < this.dimension; l++) {
            //Centroid coordinate of the point
            double centroidCoordinatePoint;
            if (this.weight != 0.0) {
                centroidCoordinatePoint = this.coordinates[l] / this.weight;
            } else {
                centroidCoordinatePoint = this.coordinates[l];
            }
            //Centroid coordinate of the centre
            double centroidCoordinateCentre;
            if (centre.weight != 0.0) {
                centroidCoordinateCentre = centre.coordinates[l] / centre.weight;
            } else {
                centroidCoordinateCentre = centre.coordinates[l];
            }
            distance += (centroidCoordinatePoint - centroidCoordinateCentre) *
                    (centroidCoordinatePoint - centroidCoordinateCentre);

        }
        return distance * this.weight;
    }


}