hybridHclust {hybridHclust}R Documentation

Hybrid hierarchical clustering using mutual clusters.

Description

Top-down clustering (tsvq) is applied to data with constraint that mutual clusters cannot be divided. Within each mutual cluster, tsvq is re-applied to yeild a top-down hybrid in which mutual cluster structure is retained.

Usage

 hybridHclust(x, themc=NULL, trace=FALSE) 

Arguments

x A data matrix whose rows are to be clustered
themc An object representing the mutual clusters in x, typically generated by mutualCluster. If it is not provided, it will be calculated.
trace Should internal steps be printed as they execute?

Details

A mutual cluster is a set of points that should never be broken (see help for ‘mutualCluster’ for a more precise definition). hybridHcclust uses this idea to construct a top-down clustering in which mutual clusters are never broken. This is achieved by temporarily “fusing” together all points in a mutual cluster so that they have equal coordinates, running tsvq, and then re-running tsvq within each mutual cluster. The resultant top-down clusterings are then “stitched” together to form a single top-down clustering.

Only maximal mutual clusters are constrained to not be broken. Thus if points A, B, C, D are a mutual cluster and points A, B are also a mutual cluster, only the four points will be forbidden from being broken.

Value

A dendrogram in hclust format.

Author(s)

Hugh Chipman

See Also

tsvq

Examples

x <- cbind(c(-1.4806,1.5772,-0.9567,-0.92,-1.9976,-0.2723,-0.3153),
c( -0.6283,-0.1065,0.428,-0.7777,-1.2939,-0.7796,0.012))
hyb1 <- hybridHclust(x)
par(mfrow=c(1,2))
plot(x, pch = as.character(1:nrow(x)), asp = 1)
plot(hyb1)

# also works 
mc1 <- mutualCluster(x)
hyb1 <- hybridHclust(x,mc1)

[Package hybridHclust version 1.0-0 Index]