Internal cluster validity indices

validate_clusters() reports the connectivity and Dunn index of a clustering, computed on the dissimilarity as.dist(1 - S).

Usage

validate_clusters(clust)

Arguments

clust

An outrank_clust object from cluster_traces().

Value

A named numeric vector with connectivity and dunn.

Details

Connectivity (to be minimised) and the Dunn index (to be maximised) are obtained from the clValid package. If clValid is not installed, the function returns NA values with an informative message.

Examples

m <- matrix(0.1, 6, 6); m[1:3, 1:3] <- 0.9; m[4:6, 4:6] <- 0.9
diag(m) <- 1; dimnames(m) <- list(1:6, 1:6)
crit <- criterion(m, "similarity", indifference = 0.3, similarity = 0.95)
tr <- as_traces(data.frame(case = as.character(1:6), act = "x",
                           ts = as.POSIXct("2020-01-01")),
                "case", "act", "ts")
clust <- cluster_traces(outrank_similarity(tr, crit), k = 2, seed = 1)
validate_clusters(clust)
#> connectivity         dunn 
#>           NA           13