Implementation of k-means clustering algorithm in C

Implementation of k-means clustering algorithm in C

• 1.
  /***************************************************************/ /* A programthat implements K-means clustering algorithm */ /***************************************************************/ #include<stdio.h> #include<conio.h> #include<fstream.h> #include<dos.h> #include<math.h> #include"E:KMCheaderGRAP.H" // To get number of the corresponding cluster int get_cluster_no(double dist[][5],int i,int centers) { int j; double min; min=dist[i][0]; for(j=0;j<centers;j++) { if(min>dist[i][j]) { min=dist[i][j]; } }
• 2.
  for(j=0;j<centers;j++) { if(min==dist[i][j]) { break; } } return j; } void cal_new_centers(doublex[],double y[],double xc[],double yc[],int points,int centers) { double x1[50],y1[50]; // To store data points double dist[50][5];// dist[i][j] : Distance from i th data point to j the cluster int i,j; int a[5]; // a[j]: To store number of points in the j th cluster int cluster_no[50]; // Number of the cluster the point belongs to static int color=2; // To compute distances to each point from centers
• 3.
  for(i=0;i<points;i++) { for(j=0;j<centers;j++) { // City blockdistance dist[i][j]=abs(x[i]-xc[j])+abs(y[i]-yc[j]); } } for(i=0;i<points;i++) { cluster_no[i]=get_cluster_no(dist,i,centers); } for(i=0;i<5;i++) { a[i]=0; } for(i=0;i<50;i++) { x1[i]=0; y1[i]=0; } // To calculate new centers
• 4.
  for(i=0;i<points;i++) { for(j=0;j<centers;j++) { if(cluster_no[i]==j) { x1[j]+=x[i]; y1[j]+=y[i]; a[j]++; } } } setcolor(color); color=color+3; for(j=0;j<centers;j++) { xc[j]=x1[j]/a[j]; yc[j]=y1[j]/a[j]; circle(xc[j]*10,yc[j]*10,3); } }
• 5.
  void main() { clrscr(); ginit(); ifstream f; doublex[50],y[50]; // To store data points double xc[5],yc[5]; // To store centers double *p; // To store xc[] and y[] respectively int points; // Number of points int centers; // Number of centers int i,j; // Reading the data points // f.open("E:/KMC/data/points.txt"); f>>points; for(i=0;i<points;i++) { f>>x[i]>>y[i];
• 6.
  } f.close(); // End ofreading the data points // // Displaying data points // for(i=0;i<points;i++) { circle(x[i]*10,y[i]*10,2); } // End of displaying data points // // Reading the centers // f.open("E:/KMC/data/centers.txt"); f>>centers; for(i=0;i<centers;i++) { f>>xc[i]>>yc[i]; }
• 7.
  f.close(); // End ofreading the centers // // Displaying initial centroids // for(i=0;i<centers;i++) { setcolor(4); circle(xc[i]*10,yc[i]*10,3); } // End of displaying initial centroids // for(i=0;i<4;i++) { cal_new_centers(x,y,xc,yc,points,centers); delay(500); } getch(); gexit(); }