MultiDendrograms is a program to make the Hierarchical Clustering of real data. It implements variable-group algorithms to solve the non-uniqueness problem found in the standard pair-group algorithms and implementations. This problem arises when two or more minimum distances between different clusters are equal during the amalgamation process. The standard approach consists in choosing a pair, breaking the ties between distances, and proceeds in the same way until the final hierarchical classification is obtained. However, different clusterings are possible depending on the criterion used to break the ties (usually a pair is just chosen at random!).
The variable-group algorithms group more than two clusters at the same time when ties occur, given rise to a graphical representation called multidendrogram. Their main properties are: when there are no ties, the variable-group algorithms give the same results as the pair-group ones; they always give a uniquely determined solution; in the multidendrogram representation for the results one can explicitly observe the occurrence of ties during the agglomerative process, and the height of any fusion interval (the bands in the program) indicates the degree of heterogeneity inside the corresponding cluster.
Go to MultiDendrograms page.
Radatools is a set of freely distributed programs to analyze Complex Networks. In particular, it includes very useful programs for Communities Detection and Mesoscales Determination.
Go to Radatools page.