Hi folks, A follow up - this problem happens only stochastically. Further, a little trial and error indicates that using mathod="Laplace" or method="AGQ" reduces the frequency of the problem. Why? I have no idea, and even this could be my own wishful interpretation of my trial and error. -Hank On Dec 20, 2006, at 4:20 PM, Martin Henry H. Stevens wrote:
> Hi folks, > I am not providing a small replicable example, because I assume the > problem is related to my quirky data (~650 obs.). > I am using the latest lme4, matrix and coda, and R 2.4.0. > > I frequently get the following error message for this particular lmer > model. I do not get this message for the vast majority of my uses of > mcmcsamp. > > I was wondering if it might be characteristic of particular kinds of > problems. > >> modb <- lmer(log(basal+1) ~ nutrient*amd + (1|rack) + (1| > gen:amd), data=dat.b2) > >> mod.mc <- mcmcsamp(modb, n=10^4) > > Error: Matrix is not pd after safe_pd_matrix! > Error in t(.Call(mer_MCMCsamp, object, saveb, n, trans, verbose)) : > error in evaluating the argument 'x' in selecting a method for > function 't' > > Cheers, > Hank > > Dr. Hank Stevens, Assistant Professor > 338 Pearson Hall > Botany Department > Miami University > Oxford, OH 45056 > > Office: (513) 529-4206 > Lab: (513) 529-4262 > FAX: (513) 529-4243 > http://www.cas.muohio.edu/~stevenmh/ > http://www.muohio.edu/ecology/ > http://www.muohio.edu/botany/ > > "E Pluribus Unum" > > ______________________________________________ > [email protected] 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. Dr. Hank Stevens, Assistant Professor 338 Pearson Hall Botany Department Miami University Oxford, OH 45056 Office: (513) 529-4206 Lab: (513) 529-4262 FAX: (513) 529-4243 http://www.cas.muohio.edu/~stevenmh/ http://www.muohio.edu/ecology/ http://www.muohio.edu/botany/ "E Pluribus Unum" ______________________________________________ [email protected] 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.
