[R] cluster/snow question

[Luke Tierney]

ls() looks in its calling environment, which in this case would be the
internals of the snow mechnism.  If you want ls of the global
environment use one of

     clusterEvalQ(cl, ls())
     clusterCall(cl, ls, .GlobalEnv)

luke

On Wed, 10 Sep 2008, tolga.i.uzuner at jpmorgan.com wrote:

> 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
>>
>>
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>
> --
> Dipl.-Tech. Math. Markus Schmidberger
>
> Ludwig-Maximilians-Universit?? M??chen
> IBE - Institut f?? medizinische Informationsverarbeitung,
> Biometrie und Epidemiologie
> Marchioninistr. 15, D-81377 Muenchen
> URL: http://ibe.web.med.uni-muenchen.de
> Mail: Markus.Schmidberger [at] ibe.med.uni-muenchen.de
> Tel: +49 (089) 7095 - 4599
>
>
>
>
>
> 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]]
>
>

-- 
Luke Tierney
Chair, Statistics and Actuarial Science
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa                  Phone:             319-335-3386
Department of Statistics and        Fax:               319-335-3017
    Actuarial Science
241 Schaeffer Hall                  email:      luke at stat.uiowa.edu
Iowa City, IA 52242                 WWW:  http://www.stat.uiowa.edu