Hi everybody, I have a problem with a cluster analysis.
I am trying to use hclust, method=ward.
The Ward method works with SQUARED Euclidean distances.
Hclust demands "a dissimilarity structure as produced by dist".
Yet, dist does not seem to produce a table of squared euclidean distances,
starting from cosines.
In fact, computing manually the squared euclidean distances from cosines
(d=2(1-cos)) produces a different outcome.
As a consequence, using hclust with ward method on a table of cosines
tranformed into distances with dist, produces a different dendrogram than
other programs for hierarchical clustering with ward method (i.e.
multidendrograms). Weird right??
Computing manually the distances and then feeding them to hclust produces
an error message. So, I am wondering, what the hell is this dist function
doing?!
thanks!
marianna
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