[R-sig-ME] GNLS Crash
Viechtbauer Wolfgang (STAT)
Wolfgang.Viechtbauer at STAT.unimaas.nl
Fri Sep 26 18:00:19 CEST 2008
I'm trying to fit a marginal (longitudinal) model with an exponential serial correlation function to the Orange tree data set. However, R crashes frequently when using the gnls() function. With the following simple example, I was able to reproduce the problem.
gnls.exp <- gnls(circumference ~ Asym/(1 + exp(-(age-xmid)/scal)) ,
data = Orange, correlation = corExp(form = ~1 | Tree),
start = c(Asym=150, xmid=750, scal=300))
On my and one other computer, R usually crashes when calling the gnls() function with this code three times in a row. I stumbled across this when trying to fit this model with different starting values.
system i386, mingw32
svn rev 46428
version.string R version 2.7.2 (2008-08-25)
Can anybody help figure out what causes this problem?
Department of Methodology and Statistics
University of Maastricht, The Netherlands
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