Some difficulties with soft k-means
If we measure distances in centimeters instead of inches
we get different soft assignments.
It would be much better to have a method that is
invariant under linear transformations of the data
space (scaling, rotating ,elongating)
Clusters are not always round.
It would be good to allow different shapes for different
clusters.
Sometimes its better to cluster by using low-density
regions to define the boundaries between clusters rather
than using high-density regions to define the centers of
clusters.