coef.hclust {cluster} R Documentation

## Agglomerative / Divisive Coefficient for 'hclust' Objects

### Description

Computes the “agglomerative coefficient” (aka “divisive coefficient” for diana), measuring the clustering structure of the dataset.

For each observation i, denote by m(i) its dissimilarity to the first cluster it is merged with, divided by the dissimilarity of the merger in the final step of the algorithm. The agglomerative coefficient is the average of all 1 - m(i). It can also be seen as the average width (or the percentage filled) of the banner plot.

### Value

a number specifying the agglomerative (or divisive for diana objects) coefficient as defined by Kaufman and Rousseeuw, see agnes.object $ac or diana.object$ dc.

### Examples

data(agriculture)
aa <- agnes(agriculture)
coef(aa) # really just extracts aa\$ac
coef(as.hclust(aa))# recomputes
coefHier(aa)       # ditto



[Package cluster version 2.1.4 Index]