Philip, If you are using WinBUGS 1.4, then the poor performance of the inprod function is a known problem. An "inprod2" function was introduced in 1.4.3 to improve performance. See
http://www.mrc-bsu.cam.ac.uk/bugs/winbugs/contents.shtml#problems You might try using that. For WinBUGS problems, you should probably try the BUGS mailing list before this one: http://www.jiscmail.ac.uk/lists/bugs.html Martyn Quoting Ben Bolker <bol...@ufl.edu>: > > > > Philip A. Viton wrote: > > > > > > I'm new to bugs, so please bear with me. Can someone tell me if the > > following two models are doing the same thing? The reason I ask is > > that with the same data, the first (based on 4 separate coeffs > > a1--a4) takes about 50 secs, while the second (based on a vectorized > > form, a[]) takes about 300. The means are about the same, though > > R-hat's in the second version are quite a bit better. > > > > The model definitions do seem to be formally equivalent, but BUGS > is a pretty big-ugly-black-box thing, and your timing (and Rhats) > seem to be pretty good evidence that WinBUGS is *not* constructing > the same sampler in both cases. (Do the posterior distributions agree > once you get to convergence?) > > You could try the same model in JAGS (the R2jags package lets > you use the same R code to call it, just substituting "jags()" for > "bugs()" if you wanted to pursue this further. In my limited experience > JAGS is usually slower than WinBUGS but it's a good cross-check. > > > Philip A. Viton wrote: > > > > (Also, and completely unrelated: is there any way to get more than 2 > > decimal places in the display of the means?) > > > > [snip snip snip] > > > > print(bugs.object,digits=5) > > Ben Bolker > > -- > View this message in context: > http://www.nabble.com/R2winbugs-%3A-vectorization-tp21019193p21021187.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. > ----------------------------------------------------------------------- This message and its attachments are strictly confidenti...{{dropped:8}} ______________________________________________ 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.
