


> Date: Mon, 21 Jan 2008 14:38:18 +0100
> From: Roger.Bivand@nhh.no
> To: luca_moiana@hotmail.com
> CC: r-sig-geo@stat.math.ethz.ch
> Subject: Re: [R-sig-Geo] ggwr and memory problems
> 
> On Mon, 21 Jan 2008, Luca Moiana wrote:
> 
> > Dear List,
> >
> > Here is my problem:
> >
> > I wanna run a ggwr on a 9000 records Spatial Points Data Frame using R 
> > on a Windows Machine (Dual processor, 4 GB RAM).
> 
> Have you tuned Windows memory use as discussed in the R for Windows FAQ - 
> section 2.9? The binaries are 32-bit, and need to be told how much memory 
> to use when trying to carry out memory intensive work.

We tried this but didn't change anything.


> 
> >
> > When I try to calculate bandwidth using:
> >
> > Sdati14400test.sel
> > <- ggwr.sel(E14400 ~ V211 + V213 + V240 + V313 + V321 + V322 + V331511 +
> > LnMPI25l.max + B:A, family = poisson(link = log), data = Sdati14400test,
> > coords=Sdati14400test.coords, adapt = FALSE, gweight = gwr.gauss, verbose =
> > TRUE, longlat = FALSE)
> >
> > I get a memory allocation error saying that the software is not able to 
> > allocate a 749 Mb memory.
> >
> > Any suggestion??
> 
> It isn't strictly necessary to use all the observations to find the 
> bandwidth - take a couple of 5% samples and see if the results differ 
> much.

I didn't know that and I would try, but then I'll have memory problems when I try to run ggwr??
Is there a command to obtain a random 5% sample??


> 
> >
> > I can also switch and use the same machine with a 64bit Ubuntu SO.
> >
> 
> You can try that, but consider dividing the fit.points up into chunks, and 
> running several R processes when actually fitting the ggwr model. The data 
> points stay the same, but fit subsets of the fit.points in separate 
> processes.

I don't have fit.points cause I'm working on the entire Lombardy Region (Northern Italy) and I'd like to compare the model from ggwr with glm models a colleague obtained from a regular glm.

MANY THANKS


> 
> ggwr() has not (yet) been adapted for using a cluster, but gwr() has and a 
> snow socket cluster will run happily on Linux there, and since it is run 
> within the function, it concatenates the results before returning. If this 
> would be useful of ggwr(), consider taking a look at the code.
> 
> Roger
> 
> >
> > THANK A LOT
> >
> >
> >
> > Luca Moiana
> >
> >
> > _________________________________________________________________
> >
> >
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> >
> > _______________________________________________
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> > R-sig-Geo@stat.math.ethz.ch
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> >
> 
> -- 
> Roger Bivand
> Economic Geography Section, Department of Economics, Norwegian School of
> Economics and Business Administration, Helleveien 30, N-5045 Bergen,
> Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
> e-mail: Roger.Bivand@nhh.no
> 

_________________________________________________________________


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