I don't have access to EM. But beware of this: The word seed has different meanings for FASTCLUS and HPCLUS. For the former it is a set of cluster centroids. For the later it is a starting number for pseudo-random number generation.  Part 3 of the link proposes a way to select the optimal number of clusters (k) using HPCLUS and then to feed that number into FASTCLUS to get better clusters. In my view, it is only worth doing that for large problems. For smaller problems, running FASTCLUS reperatedly over a range of k-values does the job. ... View more