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
>
> _______________________________________________
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>



-- 
Rich Calaway
Documentation Manager
Revolution Analytics, Inc.
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richcalaway@revolutionanalytics.com
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