Parallel computing on Windows (foreach)
It's sad, but not an impossible result with synchronization overhead (though I wouldn't have guessed it would be that bad) -- can you try it on a more reasonable benchmark? Also, that advice might be somewhat out of date -- why not use the tools provided in library(parallel) available for recent versions of R? Michael
On Thu, Jul 26, 2012 at 8:00 AM, deep123 <deps_123 at yahoo.co.in> wrote:
Hello all,
My problem is similar to Sergey's.
I could not try what Mario suggested, since doMPI is not available for
windows.
I have tried the Cedrick's commands, i.e.
cl.tmp = makeCluster(rep("localhost",2), type="SOCK")
registerDoSNOW(cl.tmp)
but this is instead increasing the time taken. For Sergy's set of commands,
i get,
x <- numeric(10000) system.time(for(i in 1:10000) x[i] <- sqrt(i))
user system elapsed 0.03 0.00 0.03
system.time(system.time(x <- foreach(i=1:10000, .combine="c") %do% sqrt(i)))
user system elapsed 4.71 0.00 4.71
system.time(system.time(x <- foreach(i=1:10000, .combine="c") %dopar% sqrt(i)))
user system elapsed 7.35 1.07 127.06 i.e. %dopar% is taking longer than %do% Please guide me. -- View this message in context: http://r.789695.n4.nabble.com/Parallel-computing-on-Windows-foreach-tp2256082p4637925.html Sent from the R help mailing list archive at Nabble.com. [[alternative HTML version deleted]]
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