Computes Rousseeuw's silhouette (Rousseeuw, 1987) for a partition of keywords on the smoothed occurrence curves \(f_j(t)\). The within and between distances are pairwise functional \(L_2\) distances. Singleton classes contribute zero, following Rousseeuw's convention.
References
Rousseeuw, P.J. (1987) Silhouettes: a graphical aid to the interpretation and validation of cluster analysis. Journal of Computational and Applied Mathematics 20, 53–65.
See also
ljmds.pipeline() which produces the (f, labels)
inputs, ljmds.select() which uses this criterion to pick
(h, k).