Partitional versus hierarchical A partitional clustering is a division of the set of data objects into subsets(clusters) a hierarchical clustering is a set of nested clusters that are organized as a tree Each node (cluster)in the tree except for the leaf nodes)is the union of its children(sub-clusters) The root of the tree is the cluster containing all the objects Often, but not always the leaves of the tree are singleton clusters of individual data objects 8/20/2016 PATTERN RECOGNITIONPartitional versus hierarchical A partitional clustering is a division of the set of data objects into subsets (clusters). A hierarchical clustering is a set of nested clusters that are organized as a tree. Each node (cluster) in the tree (except for the leaf nodes) is the union of its children (sub-clusters). The root of the tree is the cluster containing all the objects. Often, but not always, the leaves of the tree are singleton clusters of individual data objects. 8/20/2016 PATTERN RECOGNITION 6