comembership: Calculates the comemberships of all pairs of a vector of...

Description Usage Arguments Details Value References Examples

View source: R/comembership.r

Description

For a set of clustering labels, this function computes the comembership of all pairs of observations. Basically, two observations are said to be comembers if they are clustered together.

Usage

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Arguments

labels

a vector of n clustering labels

Details

Tibshirani and Walther (2005) use the term 'co-membership', which we shorten to 'comembership'. Some authors instead use the terms 'connectivity' or 'co-occurrence'.

We use the Rcpp package to improve the runtime speed of this function.

Value

a vector of choose(n, 2) comembership bits

References

Tibshirani, R. and Walther, G. (2005), Cluster Validation by Prediction Strength, _Journal of Computational and Graphical Statistics_, 14, 3, 511-528. http://amstat.tandfonline.com/doi/abs/10.1198/106186005X59243.

Examples

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# We generate K = 3 labels for each of n = 10 observations and compute the
# comembership for all 'n choose 2' pairs.
set.seed(42)
K <- 3
n <- 10
labels <- sample.int(K, n, replace = TRUE)
comembership_out <- comembership(labels)
comembership_out

# Notice that the number of comemberships is 'n choose 2'.
length(comembership_out) == choose(n, 2)

clusteval documentation built on May 29, 2017, 11:45 p.m.