Linkage Methods 
The Linkage type exposes the following members.
Name  Description  

CentroidLinkage 
Computes the distance between two clusters as the difference between centroids.
 
CompleteLinkage 
Computes the distance between two clusters as the greatest distance
between any two objects in the different clusters (furthest neighbors).
 
MedianLinkage 
Computes the distance between two clusters as the difference between centroids,
using the size of each cluster as a weighting factor.
 
SingleLinkage 
Computes the distance between two clusters as the distance of the
two closest objects (nearest neighbors) in the clusters.
 
UnweightedAverageLinkage 
Computes the distance between two clusters as the average distance between
all pairs of objects in the two different clusters.
 
WardLinkage 
Computes the distance between two clusters using Ward's method.
 
WeightedAverageLinkage 
Computes the distance between two clusters as the average distance between
all pairs of objects in the two different clusters, using the size of each
cluster as a weighting factor.
