K-means Clustering Algorithm: Java Code

The Java Code for K-means clustering is given below:
//Aim:To implement Kmeans clustering algorithm. //Program import java.util.*; class k_means { static int count1,count2,count3; static int d[]; static int k[][]; static int tempk[][]; static double m[]; static double diff[]; static int n,p; static int cal_diff(int a) // This method will determine the cluster in which an element go at a particular step. { int temp1=0; for(int i=0;i<p;++i) { if(a>m[i]) diff[i]=a-m[i]; else diff[i]=m[i]-a; } int val=0; double temp=diff[0]; for(int i=0;i<p;++i) { if(diff[i]<temp) { temp=diff[i]; val=i; } }//end of for loop return val; } static void cal_mean() // This method will determine intermediate mean values { for(int i=0;i<p;++i) m[i]=0; // initializing means to 0 int cnt=0; for(int i=0;i<p;++i) { cnt=0; for(int j=0;j<n-1;++j) { if(k[i][j]!=-1) { m[i]+=k[i][j]; ++cnt; }} m[i]=m[i]/cnt; } } static int check1() // This checks if previous k ie. tempk and current k are same.Used as terminating case. { for(int i=0;i<p;++i) for(int j=0;j<n;++j) if(tempk[i][j]!=k[i][j]) { return 0; } return 1; } public static void main(String args[]) { Scanner scr=new Scanner(System.in); /* Accepting number of elements */ System.out.println("Enter the number of elements "); n=scr.nextInt(); d=new int[n]; /* Accepting elements */ System.out.println("Enter "+n+" elements: "); for(int i=0;i<n;++i) d[i]=scr.nextInt(); /* Accepting num of clusters */ System.out.println("Enter the number of clusters: "); p=scr.nextInt(); /* Initialising arrays */ k=new int[p][n]; tempk=new int[p][n]; m=new double[p]; diff=new double[p]; /* Initializing m */ for(int i=0;i<p;++i) m[i]=d[i]; int temp=0; int flag=0; do { for(int i=0;i<p;++i) for(int j=0;j<n;++j) { k[i][j]=-1; } for(int i=0;i<n;++i) // for loop will cal cal_diff(int) for every element. { temp=cal_diff(d[i]); if(temp==0) k[temp][count1++]=d[i]; else if(temp==1) k[temp][count2++]=d[i]; else if(temp==2) k[temp][count3++]=d[i]; } cal_mean(); // call to method which will calculate mean at this step. flag=check1(); // check if terminating condition is satisfied. if(flag!=1) /*Take backup of k in tempk so that you can check for equivalence in next step*/ for(int i=0;i<p;++i) for(int j=0;j<n;++j) tempk[i][j]=k[i][j]; System.out.println("\n\nAt this step"); System.out.println("\nValue of clusters"); for(int i=0;i<p;++i) { System.out.print("K"+(i+1)+"{ "); for(int j=0;k[i][j]!=-1 && j<n-1;++j) System.out.print(k[i][j]+" "); System.out.println("}"); }//end of for loop System.out.println("\nValue of m "); for(int i=0;i<p;++i) System.out.print("m"+(i+1)+"="+m[i]+" "); count1=0;count2=0;count3=0; } while(flag==0); System.out.println("\n\n\nThe Final Clusters By Kmeans are as follows: "); for(int i=0;i<p;++i) { System.out.print("K"+(i+1)+"{ "); for(int j=0;k[i][j]!=-1 && j<n-1;++j) System.out.print(k[i][j]+" "); System.out.println("}"); } } } /* OUTPUT C:\Users\Aditya\Desktop\aditya>javac k_means.java C:\Users\Aditya\Desktop\aditya>java k_means Enter the number of elements 8 Enter 8 elements: 2 3 6 8 12 15 18 22 Enter the number of clusters: 3 At this step Value of clusters K1{ 2 } K2{ 3 } K3{ 6 8 12 15 18 22 } Value of m m1=2.0 m2=3.0 m3=13.5 At this step Value of clusters K1{ 2 } K2{ 3 6 8 } K3{ 12 15 18 22 } Value of m m1=2.0 m2=5.666666666666667 m3=16.75 At this step Value of clusters K1{ 2 3 } K2{ 6 8 } K3{ 12 15 18 22 } Value of m m1=2.5 m2=7.0 m3=16.75 At this step Value of clusters K1{ 2 3 } K2{ 6 8 } K3{ 12 15 18 22 } Value of m m1=2.5 m2=7.0 m3=16.75 The Final Clusters By Kmeans are as follows: K1{ 2 3 } K2{ 6 8 } K3{ 12 15 18 22 } */

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