Can you provide a little more information. What operating system are you using? Have you monitored the CPU and memory utilizations of the processes? Do you have enough physical memory; e.g., are you paging? How big are the matrices that you are processing; e.g., str(tTA) and object.size(tTA). This is the type of information that would be required to make an informed guess at what is happening.
On Wed, Nov 10, 2010 at 9:07 AM, Santosh Srinivas <santosh.srini...@gmail.com> wrote: > My parallel code is running slower than my non-parallel code! Can someone > pls advise what am I doing wrong here? > > t and tTA are simple matrices of equal dimensions. > > #NON PARALLEL CODE > > nCols=ncol(t) > nRows=nrow(t) > tTA = matrix(nrow=nRows,ncol=nCols) > > require(TTR) > system.time( > for (i in 1:nCols) { > x = t[,i] > xROC = ROC(x) > tTA[,i]=xROC > > } > ) > > user system elapsed > 123.24 0.07 123.47 > > > # PARALLEL CODE > > nCols=ncol(t) > nRows=nrow(t) > tTA = matrix(nrow=nRows,ncol=nCols) > > require(doSMP) > workers <- startWorkers(4) # My computer has 4 cores > registerDoSMP(workers) > system.time( > foreach (i=1:nCols) %dopar%{ > x = t[,i] > xROC = ROC(x) > tTA[,i]=xROC > > } > ) > > # stop workers > stopWorkers(workers) > > It is taking ages! > > Thanks, > S > > ______________________________________________ > 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. > -- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem that you are trying to solve? ______________________________________________ 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.