R: Calinski-Harabasz index

calinhara {fpc} | R Documentation

## Calinski-Harabasz index

### Description

Calinski-Harabasz index for estimating the number of clusters, based on an observations/variables-matrix here. A distance based version is available through `cluster.stats`.

### Usage

      calinhara(x,clustering,cn=max(clustering))

### Arguments

`x` | data matrix or data frame.
`clustering` | vector of integers. Clustering.
`cn` | integer. Number of clusters.

### Value

Calinski-Harabasz statistic, which is `(n-cn)*sum(diag(B))/((cn-1)*sum(diag(W)))`. B being the between-cluster means, and W being the within-clusters covariance matrix.

### Author(s)

Christian Hennig c.hennig@ucl.ac.uk http://www.homepages.ucl.ac.uk/~ucakche

### References

Calinski, T., and Harabasz, J. (1974) A Dendrite Method for Cluster Analysis, Communications in Statistics, 3, 1-27.

### See Also

`cluster.stats`

### Examples

      set.seed(98765)
      iriss <- iris[sample(150,20),-5]
      km <- kmeans(iriss,3)
      round(calinhara(iriss,km$cluster),digits=2)

[Package fpc version 2.1-10 Index]