clue (version 0.2-8)

validity: Validity Measures for Partitions and Hierarchies

Description

Compute validity measures for partitions and hierarchies, attempting to measure how well these clusterings capture the underlying structure in the data they were obtained from.

Usage

cl_validity(x, ...)
## S3 method for class 'default':
cl_validity(x, d, ...)

Value

• A list of class "cl_validity" with the computed validity measures.

Details

cl_validity is a generic function.

For partitions, its default method gives the dissimilarity accounted for, defined as $1 - a_w / a_t$, where $a_t$ is the average total dissimilarity, and the average within dissimilarity $a_w$ is given by $$\sum_{i,j} \sum_k m_{ik}m_{jk} d_{ij} / \sum_{i,j} \sum_k m_{ik}m_{jk}$$ where $d$ and $m$ are the dissimilarities and memberships, respectively, and the sums are over all pairs of objects and all classes.

For hierarchies, currently no validity measures are computed by default. For the results of using agnes and diana, the agglomerative and divisive coefficients are provided.

See Also

cluster.stats in package fpc for a variety of cluster validation statistics; fclustIndex in package e1071 for several fuzzy cluster indexes; clustIndex in package cclust; silhouette in package cluster.