[R] Snow & rvpm

From: vittorio <vdemart1_at_tin.it>
Date: Fri 02 Dec 2005 - 06:13:47 EST


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 Received on Fri Dec 02 06:12:53 2005

This archive was generated by hypermail 2.1.8 : Fri 03 Mar 2006 - 03:41:25 EST