Thanks for looking into this -- it seems a functional if somewhat inelegant
way would be to use a tryCatch function on a VERY simple foreach statement.
 This is what I'm using now.  If you guys come up with a more "official"
statement that would be great!  Cheers!

--j


On Sat, Feb 2, 2013 at 7:55 PM, Rich Calaway <
richcalaway@revolutionanalytics.com> wrote:

> Hi, Steve and Jonathan,
>
> It is a good idea...I'm thinking it might need to be a generic with
> specific methods for specific backends. Steve, you want to bat some ideas
> around? We could probably put together something useful for the parallel
> family (doParallel, doMC, doSNOW) in time for R 3.0...
>
> Rich Calaway
>
>
> On Sat, Feb 2, 2013 at 12:02 PM, Stephen Weston <
> stephen.b.weston@gmail.com> wrote:
>
>> Hi Jonathan,
>>
>> Sorry, there's is nothing like that in foreach.  The functions that
>> are used to provide information about the parallel backend include:
>>
>>   getDoParWorkers()
>>   getDoParName()
>>   getDoParVersion()
>>   getDoParRegistered()
>>
>> but no "health check" functions.  It's a good idea, though.  I believe
>> they include that sort of thing in database frameworks.
>>
>> By the way, I had no idea that you could use the doSNOW package
>> with snowfall, although I guess it makes sense since they give you
>> access to the cluster object.  But I've only ever tested doSNOW with
>> snow.
>>
>> - Steve
>>
>>
>> On Sat, Feb 2, 2013 at 12:19 PM, Jonathan Greenberg <jgrn@illinois.edu>
>> wrote:
>> > R-sig-hpc'ers:
>> >
>> > I've been modding some code lately to take advantage of the foreach
>> > generalization (so I don't have to write multiple statements depending
>> on
>> > the parallel backend that I have running), but I'm trying to figure out
>> how
>> > to check for a registered, but no longer running, parallel backend,
>> e.g.:
>> >
>> > require("foreach")
>> > require("snowfall")
>> > require("doSNOW")
>> > # Start a snowfall cluster and register it with foreach
>> > sfInit(cpu=2,parallel=TRUE)
>> > cl <- sfGetCluster()
>> > registerDoSNOW(cl)
>> >
>> > # Some foreach statement:
>> > d <- data.frame(x=1:10, y=rnorm(10))
>> > s <- foreach(d=iter(d, by='row'), .combine=rbind) %dopar% d
>> >
>> > # Works fine.  Now stop the cluster:
>> > sfStop()
>> > s <- foreach(d=iter(d, by='row'), .combine=rbind) %dopar% d
>> > # Doesn't work, because the snow cluster is gone.
>> >
>> > # I can manually set this, but is there some test I can do
>> > # to test for whether the cluster is working and, if not:
>> > registerDoSEQ()
>> > s <- foreach(d=iter(d, by='row'), .combine=rbind) %dopar% d
>> >
>> > # e.g.
>> > if(checkForWorkingBackend == FALSE)
>> > {
>> > registerDoSEQ()
>> > }
>> >
>> >
>> >
>> > --
>> > Jonathan A. Greenberg, PhD
>> > Assistant Professor
>> > Global Environmental Analysis and Remote Sensing (GEARS) Laboratory
>> > Department of Geography and Geographic Information Science
>> > University of Illinois at Urbana-Champaign
>> > 607 South Mathews Avenue, MC 150
>> > Urbana, IL 61801
>> > Phone: 217-300-1924
>> > http://www.geog.illinois.edu/~jgrn/
>> > AIM: jgrn307, MSN: jgrn307@hotmail.com, Gchat: jgrn307, Skype: jgrn3007
>> >
>> >         [[alternative HTML version deleted]]
>> >
>> > _______________________________________________
>> > R-sig-hpc mailing list
>> > R-sig-hpc@r-project.org
>> > https://stat.ethz.ch/mailman/listinfo/r-sig-hpc
>>
>> _______________________________________________
>> R-sig-hpc mailing list
>> R-sig-hpc@r-project.org
>> https://stat.ethz.ch/mailman/listinfo/r-sig-hpc
>>
>
>
>
> --
> Rich Calaway
> Documentation Manager
> Revolution Analytics, Inc.
> 1505 Westlake Ave North Suite 300
> Seattle, WA 98109
> richcalaway@revolutionanalytics.com
> 206-456-6086 (Direct Phone)
> 855-GET-REVO x6086 (Toll-free)
>



-- 
Jonathan A. Greenberg, PhD
Assistant Professor
Global Environmental Analysis and Remote Sensing (GEARS) Laboratory
Department of Geography and Geographic Information Science
University of Illinois at Urbana-Champaign
607 South Mathews Avenue, MC 150
Urbana, IL 61801
Phone: 217-300-1924
http://www.geog.illinois.edu/~jgrn/
AIM: jgrn307, MSN: jgrn307@hotmail.com, Gchat: jgrn307, Skype: jgrn3007

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