validity {clue} | R Documentation |
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.
cl_validity(x, ...) ## Default S3 method: cl_validity(x, d, ...)
x |
an object representing a partition or hierarchy. |
d |
a dissimilarity object from which x was obtained. |
... |
arguments to be passed to or from methods. |
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.
A list of class "cl_validity"
with the computed validity
measures.
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.