R help - Jun 2010 - Parallel computing on Windows (foreach) (Sergey Goriatchev)

foreach (or virtually anything you might use for concurrent programming)
only really makes sense if the work the "clients" are doing is
substantial
enough to overwhelm the communication overhead.  And there are many ways to
accomplish the same task more or less efficiently (for example, doing blocks
of tasks in chunks rather than passing each one as an individual job).

But more to the point, doSNOW works just fine on an SMP, no problem, it
doesn't require a cluster.

Jay


<<example code omitted>>

Not only is the sequential foreach much slower than the simple
for-loop (as least in this particular instance), but I am not quite
sure how to make foreach run parallel. Where would I get this parallel
backend? I looked at doMC and doRedis, but these do not run on
Windows, as far as I understand. And doSNOW is something to use when
you have a cluster, while I have a simple dual-core PC.

It is not really clear for how to make parallel computing work. Please,
help.

Regards,
Sergey

-- 
John W. Emerson (Jay)
Associate Professor of Statistics
Department of Statistics
Yale University
http://www.stat.yale.edu/~jay <http://www.stat.yale.edu/%7Ejay>

	[[alternative HTML version deleted]]

Hi,

I think I lost the reference email somewhere, but:
> Not only is the sequential foreach much slower than the simple
> for-loop (as least in this particular instance), but I am not quite
> sure how to make foreach run parallel. Where would I get this parallel
> backend? I looked at doMC and doRedis, but these do not run on
> Windows, as far as I understand.
See this blog post:
http://www.r-statistics.com/tag/dosmp/

-- 
Steve Lianoglou
Graduate Student: Computational Systems Biology
 | Memorial Sloan-Kettering Cancer Center
 | Weill Medical College of Cornell University
Contact Info: http://cbio.mskcc.org/~lianos/contact

John, Steve, thank you for answering my post!

On Wed, Jun 16, 2010 at 20:55, Steve Lianoglou
<mailinglist.honeypot at gmail.com> wrote:
> Hi,
>
> I think I lost the reference email somewhere, but:
>
>> Not only is the sequential foreach much slower than the simple
>> for-loop (as least in this particular instance), but I am not quite
>> sure how to make foreach run parallel. Where would I get this parallel
>> backend? I looked at doMC and doRedis, but these do not run on
>> Windows, as far as I understand.
>
> See this blog post:
> http://www.r-statistics.com/tag/dosmp/
>
> --
> Steve Lianoglou
> Graduate Student: Computational Systems Biology
> ?| Memorial Sloan-Kettering Cancer Center
> ?| Weill Medical College of Cornell University
> Contact Info: http://cbio.mskcc.org/~lianos/contact
>


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