Clustering Algorithm Based On Directed Graphs

This function finds clusters in a data set using an algorithm by Koontz et al.

The algorithm organizes a set of N objects into a directed graph that reveals clusters of
objects. Specically, the algorithm chooses a parent object for each object. The parent
object is also one of the objects in the set and may be the object itself. This parenthood
can be stated as a mapping P(n) of the object indexes into themselves. An object that is
its own parent is an orphan and becomes the root of a cluster.
Further information is provided in an accompanying document.