Algorithm 4. Pseudo-code of the Build Phase for Parallel PAM

1. repeat

2.  for p := 1 → P do in parallel

3.   for each data point Xa ϵ p do       /* All PEs do in parallel*/

4.    Select Xa as temporary Medoid

5.    for i := 1 → N do

6.     for each Medoid selected yet (including Xa)do

7.      Find the minimum Euclidean distance b/w Xi and Medoid

8.     endfor

9.     Find sum of minimum distances

10.    endfor

11.    Find minimum sum

12.   endfor

13.  endfor

14.  for p := 1 → P do        /* Only master PE will do this */

15.   Select Xa as actual Medoid for which the sum is minimum from all PEs

16.  endfor

17. until ‘K’ initial Medoids are selected