K中心点算法(K-medoids) java实现

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 package com.kmedoids;import java.util.ArrayList;public class Cluster {    private String clusterName; // 类簇名    private Medoid medoid; // 类簇的质点    private ArrayList<DataPoint> dataPoints; // 类簇中各样本点    public Cluster(String clusterName) {        this.clusterName = clusterName;        this.medoid = null; // will be set by calling setCentroid()        dataPoints = new ArrayList<DataPoint>();    }    public void setMedoid(Medoid c) {        medoid = c;    }    public Medoid getMedoid() {        return medoid;    }       public void addDataPoint(DataPoint dp) { // called from CAInstance        dp.setCluster(this);// 标注该类簇属于某点,计算欧式距离        this.dataPoints.add(dp);    }    public void removeDataPoint(DataPoint dp) {        this.dataPoints.remove(dp);    }    public int getNumDataPoints() {        return this.dataPoints.size();    }    public DataPoint getDataPoint(int pos) {        return (DataPoint) this.dataPoints.get(pos);    }    public String getName() {        return this.clusterName;    }    public ArrayList<DataPoint> getDataPoints() {        return this.dataPoints;    }}------------------------------------package com.kmedoids;import java.util.ArrayList;public class DataPoint {    private double dimension[]; //样本点的维度    private String pointName; //样本点名字    private Cluster cluster; //类簇    private double euDt;//样本点到质点的距离    public DataPoint(double dimension[], String pointName) {        this.dimension = dimension;        this.pointName = pointName;        this.cluster = null;    }    public void setCluster(Cluster cluster) {        this.cluster = cluster;    }       public double calEuclideanDistanceSum() {        double sum=0.0;        Cluster cluster=this.getCluster();        ArrayList<DataPoint> dataPoints=cluster.getDataPoints();        for(int i=0;i<dataPoints.size();i++){            double[] dims=dataPoints.get(i).getDimensioin();            for(int j=0;j<dims.length;j++){                 double temp=Math.pow((dims[j]-this.dimension[j]),2);                 sum=sum+temp;            }        }        return Math.sqrt(sum);    }       public double testEuclideanDistance(Medoid c) {        double sum=0.0;        double[] cDim=c.getDimensioin();        for(int i=0;i<dimension.length;i++){           double temp=Math.pow((dimension[i]-cDim[i]),2);           sum=sum+temp;        }        return Math.sqrt(sum);    }    public double[] getDimensioin() {        return this.dimension;    }    public Cluster getCluster() {        return this.cluster;    }    public double getCurrentEuDt() {        return this.euDt;    }    public String getPointName() {        return this.pointName;    }}-------------------------------package com.kmedoids;import java.util.ArrayList;public class Medoid{    private double dimension[]; // 质点的维度    private Cluster cluster; //所属类簇    private double etdDisSum;//Medoid到本类簇中所有的欧式距离之和    public Medoid(double dimension[]) {        this.dimension = dimension;    }    public void setCluster(Cluster c) {        this.cluster = c;    }    public double[] getDimensioin() {        return this.dimension;    }    public Cluster getCluster() {        return this.cluster;    }    public void calcMedoid() {// 取代价最小的点        calcEtdDisSum();        double minEucDisSum = this.etdDisSum;        ArrayList<DataPoint> dps = this.cluster.getDataPoints();        for (int i = 0; i < dps.size(); i++) {            double tempeucDisSum = dps.get(i).calEuclideanDistanceSum();            if (tempeucDisSum < minEucDisSum) {                dimension = dps.get(i).getDimensioin();                minEucDisSum=tempeucDisSum;            }        }    }    // 计算该Medoid到同类簇所有样本点的欧斯距离和    private void calcEtdDisSum() {        double sum=0.0;        Cluster cluster=this.getCluster();        ArrayList<DataPoint> dataPoints=cluster.getDataPoints();        for(int i=0;i<dataPoints.size();i++){            double[] dims=dataPoints.get(i).getDimensioin();            for(int j=0;j<dims.length;j++){                 double temp=Math.abs(dims[j]-this.dimension[j]);                 sum=sum+temp;            }        }        etdDisSum= sum;    }}--------------------------package com.kmedoids;import java.util.ArrayList;public class ClusterAnalysis {    private Cluster[] clusters;// 所有类簇    private int miter;// 迭代次数    private ArrayList<DataPoint> dataPoints = new ArrayList<DataPoint>();// 所有样本点    private int dimNum;//维度    public ClusterAnalysis(int k, int iter, ArrayList<DataPoint> dataPoints,int dimNum) {        clusters = new Cluster[k];// 类簇种类数        for (int i = 0; i < k; i++) {            clusters[i] = new Cluster("Cluster:" + i);        }        this.miter = iter;        this.dataPoints = dataPoints;        this.dimNum=dimNum;    }    public int getIterations() {        return miter;    }    public ArrayList<DataPoint>[] getClusterOutput() {        ArrayList<DataPoint> v[] = new ArrayList[clusters.length];        for (int i = 0; i < clusters.length; i++) {            v[i] = clusters[i].getDataPoints();        }        return v;    }       public void startAnalysis(double[][] medoids) {        setInitialMedoids(medoids);        double[][] newMedoids=medoids;        double[][] oldMedoids=new double[medoids.length][this.dimNum];        while(!isEqual(oldMedoids,newMedoids)){            for(int m = 0; m < clusters.length; m++){//每次迭代开始情况各类簇的点                clusters[m].getDataPoints().clear();            }            for (int j = 0; j < dataPoints.size(); j++) {                int clusterIndex=0;                double minDistance=Double.MAX_VALUE;                for (int k = 0; k < clusters.length; k++) {//判断样本点属于哪个类簇                    double eucDistance=dataPoints.get(j).testEuclideanDistance(clusters[k].getMedoid());                    if(eucDistance<minDistance){                        minDistance=eucDistance;                        clusterIndex=k;                    }                }               //将该样本点添加到该类簇                clusters[clusterIndex].addDataPoint(dataPoints.get(j));            }            for(int m = 0; m < clusters.length; m++){                clusters[m].getMedoid().calcMedoid();//重新计算各类簇的质点            }            for(int i=0;i<medoids.length;i++){                for(int j=0;j<this.dimNum;j++){                    oldMedoids[i][j]=newMedoids[i][j];                }            }            for(int n=0;n<clusters.length;n++){                newMedoids[n]=clusters[n].getMedoid().getDimensioin();            }            this.miter++;        }    }    private void setInitialMedoids(double[][] medoids) {        for (int n = 0; n < clusters.length; n++) {            Medoid medoid = new Medoid(medoids[n]);            clusters[n].setMedoid(medoid);            medoid.setCluster(clusters[n]);        }    }       private boolean isEqual(double[][] oldMedoids,double[][] newMedoids){        boolean flag=false;        for(int i=0;i<oldMedoids.length;i++){            for(int j=0;j<oldMedoids[i].length;j++){                if(oldMedoids[i][j]!=newMedoids[i][j]){                    return flag;                }            }        }        flag=true;        return flag;    }}--------------------------------------------package com.kmedoids;import java.util.ArrayList;import java.util.Iterator;public class TestMain {    public static void main (String args[]){        ArrayList<DataPoint> dataPoints = new ArrayList<DataPoint>();               double[] a={2,3};        double[] b={2,4};        double[] c={1,4};        double[] d={1,3};        double[] e={2,2};        double[] f={3,2};        double[] g={8,7};        double[] h={8,6};        double[] i={7,7};        double[] j={7,6};        double[] k={8,5};        double[] l={100,2};//孤立点        double[] m={8,20};        double[] n={8,19};        double[] o={7,18};        double[] p={7,17};        double[] q={7,20};        dataPoints.add(new DataPoint(a,"a"));        dataPoints.add(new DataPoint(b,"b"));        dataPoints.add(new DataPoint(c,"c"));        dataPoints.add(new DataPoint(d,"d"));        dataPoints.add(new DataPoint(e,"e"));        dataPoints.add(new DataPoint(f,"f"));        dataPoints.add(new DataPoint(g,"g"));        dataPoints.add(new DataPoint(h,"h"));        dataPoints.add(new DataPoint(i,"i"));        dataPoints.add(new DataPoint(j,"j"));        dataPoints.add(new DataPoint(k,"k"));        dataPoints.add(new DataPoint(l,"l"));        dataPoints.add(new DataPoint(m,"m"));        dataPoints.add(new DataPoint(n,"n"));        dataPoints.add(new DataPoint(o,"o"));        dataPoints.add(new DataPoint(p,"p"));        dataPoints.add(new DataPoint(q,"q"));        ClusterAnalysis ca=new ClusterAnalysis(3,0,dataPoints,2);       double[][] cen={{8,7},{8,6},{7,7}};       ca.startAnalysis(cen);       ArrayList<DataPoint>[] v = ca.getClusterOutput();        for (int ii=0; ii<v.length; ii++){            ArrayList tempV = v[ii];            System.out.println("-----------Cluster"+ii+"---------");            Iterator iter = tempV.iterator();            while(iter.hasNext()){                DataPoint dpTemp = (DataPoint)iter.next();                System.out.println(dpTemp.getPointName());            }        }    }}

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