To the best of our knowledge, alternatives to k-means such as the previous have
not been applied to RS. The simplicity and efficiency of the k-means algorithm
shadows possible alternatives. It is not clear whether density-based or hierarchical
clustering approaches have anything to offer in the RS arena. On the other hand,
message-passing algorithms have been shown to be more efficient and their graph-
based paradigm can be easily translated to the RS problem. It is possible that we see
applications of these algorithms in the coming years.