You might want to use `trace' and/or other debugging options to better understand when and why this happens.
Ravi. ____________________________________________________________________ Ravi Varadhan, Ph.D. Assistant Professor, Division of Geriatric Medicine and Gerontology School of Medicine Johns Hopkins University Ph. (410) 502-2619 email: rvarad...@jhmi.edu ----- Original Message ----- From: Ben Bolker <bbol...@gmail.com> Date: Friday, March 25, 2011 8:11 am Subject: Re: [R] a question on R optimization functions To: r-h...@stat.math.ethz.ch > Dajiang J. Liu <dajiang.liu <at> gmail.com> writes: > > > I use nlminb or optim for maximizing likelihood functions. Sometimes, > > the parameter values happen to be NA, then the program will hang there > > and iterate forever without stopping. No error message will be > > produced. So I can not use error catch method such as "try". Are there > > any suggestions how I can circumvent this problem? Maybe I can time > a > > function, and if the time exceeds a threshold, it will be stopped. > I > > am not sure if this is feasible in R. As a note, I am running > > simulations with thousands of replicates, so there needs to be a > > systematic way of doing this. Are there any suggestions on how to do > > this? Thank you very much! > > It would be very surprising (I suppose not impossible, but > *very* surprising) if this behavior were generated by R's optimization > functions; it would be much more likely for it to be an infinite > loop/hang somewhere inside your objective function. > > See ?setTimeLimit (which will fail if the problem is inside > C code that you have written ...) > > Ben Bolker > > ______________________________________________ > R-help@r-project.org mailing list > > PLEASE do read the posting guide > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@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.
