Re: [R] Snow & rvpm

From: vittorio <vdemart1_at_tin.it>
Date: Fri 02 Dec 2005 - 07:30:33 EST

Alle 19:03, giovedý 01 dicembre 2005, Martin Morgan ha scritto:
> In the example at
> http://www.stat.uiowa.edu/~luke/R/cluster/cluster.html clusterCall
> divides the parameter R by the number of nodes -- what you've done is
> calculate 999 bootstraps on each node, and compared the execution time
> to 999 bootstraps on one node.
>
> You probably want 'clusterCall' to be smart enough to partition the
> bootstraps between nodes, and then collate the results. It doesn't do
> that.

What program does it?
Vittorio

>
> vittorio <vdemart1@tin.it> writes:
> > At office, using the internal LAN at my disposal, I'm having a go at
> > parallel computing - to begin with - with pvm, rpvm & snow.
> > The two boxes are as follows
> >
> > Remote machine uffbsd:
> > CPU: Intel(R) Pentium(R) 4 CPU 2.00GHz (1994.13-MHz 686-class CPU)
> > Origin = "GenuineIntel" Id = 0xf24 Stepping = 4
> > real memory = 260046848 (248 MB)
> >
> > This machine NbBSD:
> > CPU: Mobile Intel(R) Pentium(R) 4 - M CPU 2.00GHz (1993.54-MHz 686-class
> > CPU) real memory = 536674304 (511 MB)
> >
> > And starting library snow under R I have the following situation
> >
> > clusterCall(cl, function() Sys.info()[c("sysname",
> > "release","nodename","machine")])
> > [[1]]
> > sysname release nodename machine
> > "FreeBSD" "5.4-RELEASE" "uffbsd.myd" "i386"
> >
> > [[2]]
> > sysname release nodename machine
> > "FreeBSD" "6.0-RELEASE" "NbBSD.myd" "i386"
> >
> > NOW,
> > using the example of boot in the end of page
> > http://www.stat.uiowa.edu/~luke/R/cluster/cluster.html
> >
> > I find this amazing result:
> >> system.time(cl.nuke.boot<-
> >
> > clusterCall(cl,boot,nuke.data,nuke.fun,R=999,m=1,fit.pred=new.fit,x.pred=
> >new.data)) [1] 0.0078125 0.0078125 27.9609375 0.0000000 0.0000000
> >
> >> system.time(nuke.boot<-
> >
> > boot(nuke.data,nuke.fun,R=999,m=1,fit.pred=new.fit,x.pred=new.data))
> > [1] 26.976562 0.109375 28.484375 0.000000 0.000000
> >
> > There's not that much gain in time between my cluster and the local
> > computation, isn't it.
> > Now my question is:
> > What could have been gone wrong and what should I verify?
> >
> > Ciao
> > Vittorio
> >
> > ______________________________________________
> > R-help@stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide!
> > http://www.R-project.org/posting-guide.html



R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Dec 02 06:39:13 2005

This archive was generated by hypermail 2.1.8 : Fri 02 Dec 2005 - 09:41:06 EST