Some users have reported that some foreach computations with doSNOW and
doParallel backends have been extremely slow; much slower than sequential
computations in some cases. The problem was in how these were handling
exported objects, and when exported objects were large, slowdowns could be
dramatic. Thanks to some excellent investigative work and recoding by Steve
Weston, the original author of foreach and doSNOW (and most of doParallel,
as well), a fix is now available. The code is currently available on
R-forge; I expect to push it to CRAN later in the week. For most uses,
updating doSNOW and/or doParallel should be sufficient, but Steve also
provided a small update to foreach itself that I found I needed for some
low-level interactions. The updated packages are the following:

http://download.r-forge.r-project.org/src/contrib/doParallel_1.0.2.tar.gz

http://download.r-forge.r-project.org/src/contrib/doSNOW_1.0.7.tar.gz

http://download.r-forge.r-project.org/src/contrib/foreach_1.4.1.tar.gz
-- 
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)

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