[R-sig-ME] c++ exception (unknown reason) when using an offset of the slope with glmer

[xavier.paoletti at curie.fr]

Dear all,

I am new on this forum and I hope my request follows the right format.

I use R 3.1.2 and lme1.7 on a mac OS X (snow leopard) or Windows OS.

I try to fit a longitudinal logistic mixed effect model on dose-time
response data where the response is measured several times at the same
dose. The probability of response increases with the dose.
There is a set of discrete doses (let's say 6) but most of the data are
measured at 1 or 2 doses.

I use a very simple logstic model with a random intercept and the dose
effect.
In the simplest case, there is not time effect.
Furthermore, I would like to set the slope of the dose to some value using
offset slope=1.5.

The command line,
glmer(DLTb ~ offset(slope*dose) + (1 | patid),
family=binomial,data=dataAllCRM,nAGQ=10)
gives the following error:
Under Mac OSX: (function (fr, X, reTrms, family, nAGQ = 1L, verbose = 0L,
control = glmerControl(),  :
  c++ exception (unknown reason)

Under Windows: Error: (maxstephalfit) PIRLS step-halvings failed to reduce
deviance in pwrssUpdate

Whatever the value of the offset, I get the same error.
If I remove the offset or if I remove the variable, some estimates are
obtained.

Please find attached an example of dataset as an illustration; I get the
same error for all tested datasets.


Thank you very much for your help.

Best regards,

Xavier