Class Ai4r::Clusterers::AverageLinkage
In: lib/ai4r/clusterers/average_linkage.rb
Parent: SingleLinkage

Implementation of a Hierarchical clusterer with group average linkage, AKA unweighted pair group method average or UPGMA (Everitt et al., 2001 ; Jain and Dubes, 1988 ; Sokal and Michener, 1958). Hierarchical clusteres create one cluster per element, and then progressively merge clusters, until the required number of clusters is reached. With average linkage, the distance between a clusters cx and cluster (ci U cj) the the average distance between cx and ci, and cx and cj.

  D(cx, (ci U cj) = (D(cx, ci) + D(cx, cj)) / 2

Methods

Public Instance methods

Build a new clusterer, using data examples found in data_set. Items will be clustered in "number_of_clusters" different clusters.

This algorithms does not allow classification of new data items once it has been built. Rebuild the cluster including you data element.

Protected Instance methods

return distance between cluster cx and cluster (ci U cj), using average linkage

[Validate]