Information on the number of CPU's

Dear R Users,
I am on Windows XP SP2 platform, using R version 2.7.2 . I was wondering
if there is a way to find out, within R, the number of CPU's on my machine
? I would use this information to set the number of nodes in a cluster,
depending on the machine. Sys.info() and .Platform do not carry this
information.

Thanks in advance,
Tolga Uzuner

Dear R Users,

Apologies for a somewhat basic cluster question. I am trying to come to 
grips with how variables are instantiated within the environment of each 
node in a cluster. When I run the following code, I expect to see the 
variable "x" in the environment of each node, but fail to do so. What am I 
doing wrong ?

library(snow)
noclusters<-2
cl <- makeCluster(noclusters, type = "SOCK")
clusterCall(cl,ls)
x<-1
clusterExport(cl,"x")
clusterCall(cl,ls) #expect to see x in the environment, but get back the 
same result as in the call above
stopCluster(cl)

  

library(snow)
noclusters<-2
cl <- makeCluster(noclusters, type = "SOCK")
clusterCall(cl,ls)
    

[[1]]
[1] "args" "fun" 

[[2]]
[1] "args" "fun" 

  

x<-1
clusterExport(cl,"x")
clusterCall(cl,ls) #expect to see x in the environment
    

[[1]]
[1] "args" "fun" 

[[2]]
[1] "args" "fun" 

  

stopCluster(cl)

    

Thanks in advance,
Tolga


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Many thanks. Yes, weird, somehow ls does not show the variables in the
environment, even though they are clearly there. It would be nice to
understand why that is the case, just to be clear about what is going on.

Thanks Markus,
Tolga




Markus Schmidberger <schmidb at ibe.med.uni-muenchen.de>
10/09/2008 10:45
Please respond to
schmidb at ibe.med.uni-muenchen.de


To
tolga.i.uzuner at jpmorgan.com
cc
r-help at r-project.org
Subject
Re: [R] cluster/snow question






Hi Tolga,

I am not sure why ls() is showing only "args" and "fun".

But x is at the nodes. Try this:

clusterEvalQ(cl,x<-x+3)
[[1]]
[1] 4

[[2]]
[1] 4

clusterCall(cl,function()x+5)
[[1]]
[1] 9

[[2]]
[1] 9

Best
Markus



tolga.i.uzuner at jpmorgan.com schrieb:

Dear R Users,

Apologies for a somewhat basic cluster question. I am trying to come to
grips with how variables are instantiated within the environment of each

node in a cluster. When I run the following code, I expect to see the
variable "x" in the environment of each node, but fail to do so. What am

I

doing wrong ?

library(snow)
noclusters<-2
cl <- makeCluster(noclusters, type = "SOCK")
clusterCall(cl,ls)
x<-1
clusterExport(cl,"x")
clusterCall(cl,ls) #expect to see x in the environment, but get back the

same result as in the call above
stopCluster(cl)

library(snow)
noclusters<-2
cl <- makeCluster(noclusters, type = "SOCK")
clusterCall(cl,ls)

[[1]]
[1] "args" "fun"

[[2]]
[1] "args" "fun"

x<-1
clusterExport(cl,"x")
clusterCall(cl,ls) #expect to see x in the environment

[[1]]
[1] "args" "fun"

[[2]]
[1] "args" "fun"

stopCluster(cl)

Thanks in advance,
Tolga


Generally, this communication is for informational purposes only
and it is not intended as an offer or solicitation for the purchase
or sale of any financial instrument or as an official confirmation
of any transaction. In the event you are receiving the offering
materials attached below related to your interest in hedge funds or
private equity, this communication may be intended as an offer or
solicitation for the purchase or sale of such fund(s).  All market
prices, data and other information are not warranted as to
completeness or accuracy and are subject to change without notice.
Any comments or statements made herein do not necessarily reflect
those of JPMorgan Chase & Co., its subsidiaries and affiliates.

This transmission may contain information that is privileged,
confidential, legally privileged, and/or exempt from disclosure
under applicable law. If you are not the intended recipient, you
are hereby notified that any disclosure, copying, distribution, or
use of the information contained herein (including any reliance
thereon) is STRICTLY PROHIBITED. Although this transmission and any
attachments are believed to be free of any virus or other defect
that might affect any computer system into which it is received and
opened, it is the responsibility of the recipient to ensure that it
is virus free and no responsibility is accepted by JPMorgan Chase &
Co., its subsidiaries and affiliates, as applicable, for any loss
or damage arising in any way from its use. If you received this
transmission in error, please immediately contact the sender and
destroy the material in its entirety, whether in electronic or hard
copy format. Thank you.
Please refer to http://www.jpmorgan.com/pages/disclosures for
disclosures relating to UK legal entities.
               [[alternative HTML version deleted]]