[R] cluster/snow question

[Luke Tierney]

On Tue, 9 Sep 2008, tolga.i.uzuner at jpmorgan.com wrote:

> Hi Markus,
>
> Many thanks. Is the "cluster" variable you mention below available in the
> environment of the nodes ? Specifically, within that environment, how
> could one identify the rank of that specific node ?

No -- that isn't the way snow works.  With snow the partitioning is
done on the master. If you need a node to know how many other nodes
there are or which index it represents in a clusterApply call then you
need to pass that information in the arguments.

luke

>
> My code would use that information to partition the problem.
>
> Thanks,
> Tolga
>
>
>
>
> Markus Schmidberger <schmidb at ibe.med.uni-muenchen.de>
> 09/09/2008 07:11
> 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,
>
> in SNOW you have to start a cluster with the command
>
> > library(snow)
> > cluster <- makeCluster(#nodes)
>
> The object "cluster" is a list with an object for each node and each
> object again is a list with all informations (rank, comm, tags)
> The size of the cluster is the length of the list.
>
> > #nodes == length(cluster)
>
> E.g. the rank for node one you can get by
> > cluster[[1]]$rank
>
> Best
> Markus
>
> tolga.i.uzuner at jpmorgan.com schrieb:
>> Dear R Users,
>>
>> I am attempting to use the snow package for clustering. Is there a way
> to
>> identfy, in the environment of each node, a rank for that node and also,
>
>> the total size of the cluster ?
>>
>> By way of analogy, I am looking for the functions in snow equivalent to
>> mpi.comm.rank() and mpi.comm.size() from RMPI, in case that makes things
>
>> clearer.
>>
>> 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