[R] R2winbugs : vectorization

[plummer at iarc.fr]

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 <bolker at 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 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.
>



-----------------------------------------------------------------------
This message and its attachments are strictly confidenti...{{dropped:8}}