Re: [R] "False convergence" in LME

From: Andrew Robinson <A.Robinson_at_ms.unimelb.edu.au>
Date: Sun, 15 Jun 2008 07:00:25 +1000

These are great tips from Spencer.

The other thing that I have found useful is to use a different optimizing algorithm. You can do this by:

control=lmeControl(opt = "optim")

Good luck!

Andrew

On Sat, Jun 14, 2008 at 09:45:22AM -0700, Spencer Graves wrote:
> This is a common problem, for which solutions are poorly documented.
>
> 1. Have you tried fitting simpler models, in the hopes of
> getting something that converges without complaint, then use 'update' to
> try more complicated models? It sometimes works, though often not.
>
> 2. Also, have you tried something like 'lme(...,
> control=lmeControl(returnObject=TRUE))'? If no, I suggest you try this
> first. With the error message you report, I would expect this to work,
> though it may not.
>
> 3. Finally, have you tried something like 'lme(...,
> control=lmeControl(singular.ok=TRUE))' OR 'lme(...,
> control=lmeControl(singular.ok=TRUE, returnObject=TRUE))'? I'm not
> sure, but I believe this may work when "returnObject=TRUE" does not.
>
> 4. Have you tried the following:
>
> library(FinTS)
> package.dir('nlme')
>
> I tried this just now and learned that the 'nlme'
> packages contains two non-standard subdirectories named "mlbook" and
> "scripts". The second contains files names 'ch01.R', 'ch02.R', etc.,
> which contain the R commands required to reproduce virtually all the
> figures, tables and examples in Pinheiro and Bates (2000) Mixed-Effects
> Models in S and S-PLUS (Springer). If you have not already done so, I
> recommend you get this book and use these script files to facilitate
> your study of it. Doug Bates is one of the world's leading experts in
> mixed-effects modeling, and I have learned a lot from my study of it.
>
> Hope this helps.
> Spencer Graves
>
> Rebecca Sela wrote:
> >I tried to use LME (on a fairly large dataset, so I am not including it),
> >and I got this error message:
> >
> >Error in lme.formula(formula(paste(c(toString(TargetName),
> >"as.factor(nodeInd)"), : nlminb problem, convergence error code = 1
> > message = false convergence (8)
> >
> >Is there any way to get more information or to get the potentially wrong
> >estimates from LME?
> >
> >(Also, the page in the NLMINB documentation,
> >http://netlib.bell-labs.com/cm/cs/cstr/153.pdf, has errors in it, which
> >makes it harder to check on what is happening.)
> >
> >Thank you in advance!
> >
> >Rebecca
> >
> >______________________________________________
> >R-help_at_r-project.org mailing list
> >https://stat.ethz.ch/mailman/listinfo/r-help
> >PLEASE do read the posting guide
> >http://www.R-project.org/posting-guide.html
> >and provide commented, minimal, self-contained, reproducible code.
> >
>
> ______________________________________________
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-- 
Andrew Robinson  
Department of Mathematics and Statistics            Tel: +61-3-8344-6410
University of Melbourne, VIC 3010 Australia         Fax: +61-3-8344-4599
http://www.ms.unimelb.edu.au/~andrewpr
http://blogs.mbs.edu/fishing-in-the-bay/

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Received on Sat 14 Jun 2008 - 21:07:28 GMT

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