[R] Spare some CPU cycles for testing lme?

Frank Samuelson fws4 at cdrh.fda.gov
Mon Sep 13 14:40:15 CEST 2004


If anyone has a few extra CPU cycles to spare,
I'd appreciate it if you could verify a problem that I
have encountered.  Run the code
below and tell me if it crashes your R before
completion.

library(lme4)
data(bdf)
dump<-sapply( 1:50000, function(i) {
     fm <- lme(langPOST ~ IQ.ver.cen + avg.IQ.ver.cen, data = bdf,
               random = ~ IQ.ver.cen | schoolNR);
     cat("  ",i,"\r")
     0
})

The above code simply reruns the example from the
lme help page a large number of times and returns a bunch
of 0's, so you'll need to have the lme4 and Matrix
packages installed.  It might take a while to complete,
but you can always nice it and let it run.

I'm attempting to bootstrap lme() from the lme4 package,
but it causes a
segfault after a couple hundred iterations.  This happens on
my Linux x86 RedHat 7.3, 8.0, 9.0, FC1 systems w/ 1.9.1
and devel 2.0.0 (not all possible combinations actually
tested.)
I've communicated w/ Douglas Bates about this and he
doesn't appear to have the problem.

Thanks for any help.

-Frank




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