Hi all,

I've been trying to figure out how to superimpose a histogram on a  
biplot that shows the relative contribution of each axis.  I have  
been using the NIPALS function (http://biomserv.univ-lyon1.fr/~dray/ 
files/softwares/nipals.R) to run principal component analyses.  Here  
is a toy example.

source("http://biomserv.univ-lyon1.fr/~dray/files/softwares/nipals.R")
mat=matrix(runif(100,0,1), ncol=10, nrow=10)
nipmat=nipals(mat, nf=9)
scatter(nipmat)

In the plot generated by the above "scatter" command, there is a  
histogram in the upper left corner.  I want to know how to  
superimpose that histogram on a similar plot, such as the following:

groups = as.factor(c(rep(1,2), rep(2,4), rep(3,4)))
s.arrow(dfxy=nipmat$co[,1:2]*8, sub="Day 10", possub="bottomleft",  
csub=3)
s.class(dfxy=nipmat$li[,1:2], fac=groups, cellipse=2, axesell=F,  
cstar=0 , col=c(2:3), add.plot=T)

I can create the histogram using:

plot(nipmat$eig/sum(nipmat$eig), type='h')

but I don't know how to superimpose it on the above graph.

Thanks for any  help!

Best,
Jennie


Jennie Lavine
PhD Candidate
Center for Infectious Disease Dynamics
Penn State University
505 ASI Building
(814)863-1815


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