On Thursday 16 September 2010, David Winsemius wrote: > On Sep 16, 2010, at 1:11 PM, Dylan Beaudette wrote: > > Hi, > > > > I have been trying to use the new .parallel argument with the most > > recent > > version of plyr [1] to speed up some tasks. I can run the example in > > the NEWS > > file [1], and it seems to be working correctly. However, R will only > > use a > > single core when I try to apply this same approach with ddply(). > > > > 1. http://cran.r-project.org/web/packages/plyr/NEWS > > > > Watching my CPUs I see that in both cases only a single core is > > used, and they > > take about the same amount of time. Is there a limitation with how > > ddply() > > dispatches parallel jobs, or is this task not suitable for parallel > > computing? > > Was this done in a GUI? The registerDoMC help page says: > "... registerDoMC, should not be used in a GUI environment, because > multiple processes then share the same GUI." > > I, by the way, before reading the above ran it on a Mac with the GUI > with cores=4 and did experience a slightly decreased time. The non-GUI > restriction may also explain why I couldn't get the multicore package > to do anything useful when I tried it in the past.
Interesting. I did not run it from within a GUI, rather from a linux terminal. It is a little sad that doMC will not work when called from the GUI-- as most of the users that I am currently developing a package for will be constrained to windows. Dylan -- Dylan Beaudette Soil Resource Laboratory http://casoilresource.lawr.ucdavis.edu/ University of California at Davis 530.754.7341 ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.