[R] Performance problem

[gerhard.krennrich@basf-ag.de]

Dear all,
I have a performance problem in terms of computing time.
I estimate mixed models on a fairly large number of subgroups (10000) using
lme(.) within the by(.) function and it takes hours to do the calculation
on a fast notebook under Windows.
I suspect by(.) to be a poor implementation for doing individual analysis
on subgroups.
Is there an alternative and more efficient way for doing by-group
processing within lme(.).

Here some code to give you a glimpse
gfit <- by(longdata, gen, function(x) lme(fixed=response ~ dye + C(treat,
base = 4 ),
            data=x,random =~ 1 | slide)  )

Thanks in advance & regards
Gerhard Krennrich


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