From kjetilh@umsanet.edu.bo  Mon Jan  7 18:42:44 2002
From: kjetilh@umsanet.edu.bo (kjetilh@umsanet.edu.bo)
Date: Mon, 7 Jan 2002 19:42:44 +0100 (MET)
Subject: [Rd] cluster - clusplot.default (PR#1249)
Message-ID: <200201071842.TAA02067@pubhealth.ku.dk>



    


The following code in clusplot.default (package cluster) is in error:

x1 <- cmdscale(x, k = 2, eig = TRUE)
        var.dec <- sum(x1$eig)/sum(diag(x1$x))
        if (var.dec < 0) 
            var.dec <- 0
        if (var.dec > 1) 
            var.dec <- 1
        x1 <- x1$points

x1 has components with names "points" and "eig", not "x", so 
sum(diag(x1$x)) returns 0, the division gives Inf which is later replaced 
by 1. 
So in the plot it is reported (always) that "These two components explain 
100% 
of the variability". 

Besides, is it reasonable that sum(NULL) returns 0 without at least a 
warning?

Another small point about the cluster package: it loads automatically
mva, but that is not mentioned in the Depends field in the description file.

Kjetil Halvorsen



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[Rd] cluster - clusplot.default (PR#1249)
kjetilh@umsanet.edu.bo