Hi lmer list-serve people:

I'm using lmer() in a large simulation and get the following error message:

Error in mer_finalize(ans) : Downdated X'X is not positive definite, 8.

Then the simulation quits.

My question is: How do I diagnose that lmer will give this message before I
call it?

My goal is to determing whether it will and skip the the replication in the
simulation (noting the frequency of the error), so that the entire
simulation can complete?

Kindly provide your reply directly to: Phil.Smith.Duluth.GA@gmail.com   ...
I'm not too skillful at learning how to find replies to my queries
otherwise.

Many thanks!
Phil Smith
Duluth, GA

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