I came across a KMeans implementation in Java. The number of clusters generated by the code is 3. But when I tried to change it to 2, I am getting the error: Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 2
Any help is much appreciated. Here is the code:
public class KMeans
{
public static void main(String[] args) {
int data[] = {2,4,10,12,3,20,30,11, 12, 14, 19, 21, 29, 31, 40};//,25,17,23}; // initial data
int noofclusters = 2;
int centroid[][]=new int[][]{
{0,0,0},
{2,4,30}
};
getCentroid(data,noofclusters,centroid);
}//main
public static int[][] getCentroid(int data[],int noofclusters,int centroid[][]){
int distance[][]=new int[noofclusters][data.length];
int cluster[]=new int[data.length];
int clusternodecount[]=new int[noofclusters];
centroid[0]=centroid[1];
centroid[1]=new int[]{0,0,0};
System.out.println("========== Starting to get new centroid =========");
for(int i=0;i<noofclusters;i++){
for(int j=0;j<data.length;j++){
//System.out.println(distance[i][j]+"("+i+","+j+")="+data[j]+"("+j+")-"+centroid[0][i]+"="+(data[j]-centroid[0][i]));
distance[i][j]=Math.abs(data[j]-centroid[0][i]);
System.out.print(distance[i][j]+" ,");
//System.out.println("Centroid: "+centroid[0][i]);
}
System.out.println();
}
for(int j = 0; j < data.length; j++){
int smallerDistance=0;
if(distance[0][j]<distance[1][j] && distance[0][j]<distance[2][j])
smallerDistance=0;
if(distance[1][j]<distance[0][j] && distance[1][j]<distance[2][j])
smallerDistance=1;
if(distance[2][j]<distance[0][j] && distance[2][j]<distance[1][j])
smallerDistance=2;//
centroid[1][smallerDistance]=centroid[1][smallerDistance]+data[j];
clusternodecount[smallerDistance]=clusternodecount[smallerDistance]+1;
cluster[j]=smallerDistance;
//System.out.println("Centerid at 1: "+centroid[1][smallerDistance]);
//System.out.print(cluster[j]+", ");
}
//for(int j=0;j<data.length;j++)
//System.out.println("c at out: "+cluster[j]);
System.out.println("======================================== ");
System.out.println("New clusters are ");
// cluster[]= { 0 1 0 1 0 2 2 1}
// data[]={2,4,-10,12,3,20,30,11};
for(int i=0;i<noofclusters;i++){
System.out.print("C"+(i+1)+": ");
for(int l=0;l<data.length;l++){
if(cluster[l]==i)
System.out.print(data[l]+" ,");
}
System.out.println();
}
System.out.println("======================================== ");
System.out.println("New centroid is ");
for(int j=0;j<noofclusters;j++){
centroid[1][j]=centroid[1][j]/clusternodecount[j];
System.out.print(centroid[1][j]+",");
}
System.out.println();
boolean isAchived=true;
for(int j=0;j<noofclusters;j++){
if(isAchived && centroid[0][j] == centroid[1][j]){
isAchived=true;
continue;
}
isAchived=false;
}
if(!isAchived){
getCentroid(data,noofclusters,centroid);
}
if(isAchived){
System.out.println("======================================== ");
System.out.println(" Final Cluster is ");
for(int i=0;i<noofclusters;i++){
System.out.print("C"+(i+1)+":");
for(int j=0;j<data.length;j++){
if(cluster[j]==i)
System.out.print(data[j]+" ,");
}
System.out.println();
}
}
return centroid;
}
}
