[R] error in nlme
Setzer.Woodrow at epamail.epa.gov
Wed Sep 12 22:50:16 CEST 2001
I'm getting an error from nlme that has me stymied. I have a data set
,'mydata', with variables: AChE, Dose, sex, set, and mrid; 'set' and 'mrid'
indicate two levels of nesting, with 'set' nested within 'mrid'. I want to
fit the model:
mod <- nlme(AChE ~ Cexp(Dose, A, B, m), data=mydata, fixed = A+B+M~sex,
random=A+B+m~sex | mrid/set, weights=varPower(fixed=1))
(mydata has over 1000 records, so I won't reproduce it here).
When I run this, I get the error:
Error: dim<- length of dims do not match the length of object
It turns out the error is being thrown by the statement:
dim(work$pdFactor) <- dim(pdMatrix(nlmeSt$reStruct[]))
 6 6
It looks like work$pdFactor contains information about both levels of
nesting, which is being ignored.
Does someone have an idea for a fix (or am I abusing nlme)?
I'm using :
Package Version Date
"nlme" "3.1-17" "2001/08/26"
system x86, Win32
R. Woodrow Setzer, Jr. Phone:
Experimental Toxicology Division Fax: (919) 541-5394
NHEERL MD-74; US EPA; RTP, NC 27711
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