[ADMB Users] glmm.admb in R

[Zhanpan Zhang]

Hi all,

Thanks for posting my previous email in this list, Prof. Skaug!

For the data I previously mentioned, R keeps displaying the error message
"Error matrix not positive definite in choleski_decomp" and it keeps running
and won't stop (R code is shown below, and the data has only two columns of
"y" being the response and "subject" being the random group factor).

>
problem=data.class(try(glmm.admb(y~1,random=~1,group="subject",data=data,family="nbinom"),silent=T))=="try-error"

This has been solved by adding the option "easyFlag=FALSE". However, I
simulated some other data, and the same problem of "Error matrix not
positive definite in choleski_decomp" endlessly popping out came back again
even with "easyFlag=FLASE".

I am actually applying glmm.admb to a number of the simulated data (say
500), and I could accept that some of them would not be fitted very well.
But is it possible to let R jump to the next data fitting if the above
problem happens for the current data set? (the only thing I can do currently
is to force R to stop, so I could never finish this loop of fitting 500 data
sets.)

Any comments will be appreciated!


Zhanpan
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