Java DBSCAN伪代码实现

Question

我觉得我的逻辑是正确的但我认为我错过了它的语法。这是我第一次使用List或Vectors，但我觉得这是实现的最佳方式，因为我必须将数据读入算法。我正试图按照伪代码实现它。我已将expandCluster合并到DBSCAN部分，因为我觉得它更好。

伪代码

这是我的实施。忽略我所有的测试打印声明。

package dbscanAlgo;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Vector;



public class dbscanAlgo{
    public static List <Vector>Data;
    public static List <Clusters> Clusters;
    public static List <Boolean > Pvisited;
    public static List <Boolean > clustered;
    public static List  neighborpts;
    public static List  neighbors;
    public static List  noise;


public static void read(int String){

    String[] values;
     //System.out.println("Working Directory = " +
             // System.getProperty("user.dir"));

    Data= new ArrayList();
    Pvisited= new ArrayList();
    Double ve;

    try
    {
    BufferedReader in = new BufferedReader(new FileReader("wholesale.csv"));    
        String line;
        Vector<Double> v= null;
        int j =0;
        while ((line = in.readLine()) != null)  
        {
            values = line.split(",");
            v = new Vector();
            for (int i =0; i<values.length; i++)
                {
                ve = Double.parseDouble(values[i]);

                v.add(ve);

                }
            Data.add(v);
            //System.out.println(Data);
            Pvisited.add(false);
            //System.out.println(Pvisited.get(j));
            v =null;
            j++;
            }

        in.close();

    }catch( IOException ioException ) {}
}

public static void DBSCAN (int esp, int minPts){
    int c=0;
    //System.out.println(c);
    Clusters = new <Clusters> ArrayList();
    neighborpts= new ArrayList();
    for(int i=0 ; i<Data.size(); i++){
        neighborpts.add(null);
    }
    noise= new ArrayList();
    for(int i =0 ; i< Data.size(); i++){
        //System.out.println("The size of the file is: "+ Data.size());
        if(!Pvisited.get(i)){
            Pvisited.set(i,true);
            neighborpts.set(i,regionQuery(Data.get(i),esp));
            //System.out.println(neighborpts);
            int size=neighborpts.size();
            //System.out.println(minPts);
            if(size< minPts)
                //System.out.println(noise);
                noise.add(i);
                //System.out.println(noise.get(i));
        else{
            //System.out.println("HEy");
            Clusters.addAll(Data.get(i));
            //System.out.println(c);
            c++;
            //System.out.println("This is c" + c);
            Clusters C= new Clusters(c);
            C.setPoint(Data.get(c));
            Clusters.add(C);
            //System.out.println(size);
            //C.printC().toString();//System.out.print(C.printC());
            for(int j= 0; j<size;j++){
                //if P' is not visited
                    if(!Pvisited.get(neighborpts.indexOf(j))){
                        Pvisited.set(j,true);
                        neighbors.add(regionQuery((Vector) neighborpts.get(j),esp));
                        //System.out.println(neighbors);
                        int nSize=neighbors.size();
                        //System.out.println(nSize);
                        if (nSize>= minPts){
                            neighborpts.add(neighbors);
                        }
                    }
                    // if P' is not yet a member of any cluster
                    // add P' to cluster c
                    if(!clustered.get(neighborpts.indexOf(j))){
                        int x=(int) neighborpts.get(j);
                        Clusters f= Clusters.get(c);
                        ((List<Integer>) f).add(x);
                    }
            }
        }
        }
    }//end of the main for loop
}


public static double ecluediean (Vector center, Vector L){
    Double result = (double) 0;
    for(int i =0; i< center.size(); i++){
        result +=Math.pow(((double) center.get(i))-(double)(L.get(i)), 2);
    }

    return Math.sqrt(result);
}

public static List regionQuery(Vector p, int eps){
    List <Vector> n = new ArrayList();
    for(int i=0 ; i<Data.size(); i++){
         n.add(null);
    }
    double dis=0;
    for(int i =0; i<Data.size();i++){
        dis=ecluediean(p,Data.get(i));

        if(dis<= eps){

            n.set(i,Data.get(i));
        }
    }
    //System.out.println(n);
    return n;
}

public static void main(String[]args){
    int N =3;
    read(1);

    DBSCAN(3,5);


    //System.out.println(((List<Vector>) Clusters.get(0)).get(1));
}   
}

Answer 1

问题可能是您将null值放入邻居列表中。不要这样做。特别是，由于此原因，您的size不正确。

查看API，并使用例如add代替set。