Hi Daren, Here is another aproach a little bit faster taking into account that I'm using your original matrices. My session info is at the end. I'm using a 2.4 GHz Core 2-Duo processor and 3 GB of RAM.
# Data set.seed(123) m1 <- matrix(rnorm(100000), ncol=100) m2 <- matrix(rnorm(100000), ncol=100) colnames(m1)=paste('m1_',1:100,sep="") colnames(m2)=paste('m2_',1:100,sep="") # Combinations combs=expand.grid(colnames(m1),colnames(m2)) # --------------- # Option 1 #---------------- system.time(apply(combs,1,function(x) cor.test(m1[,x[1]],m2[,x[2]])$p.value)->pvalues1) # user system elapsed # 8.12 0.01 8.20 # --------------- # Option 2 #---------------- require(Hmisc) system.time(apply(combs,1,function(x) rcorr(m1[,x[1]],m2[,x[2]])$P[2])->pvalues2) # user system elapsed # 7.00 0.00 7.02 HTH, Jorge # ------------- Session Info ---------------------------- R version 2.8.0 Patched (2008-11-08 r46864) i386-pc-mingw32 locale: LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;LC_MONETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252 attached base packages: [1] stats graphics grDevices utils datasets methods base On Tue, Nov 25, 2008 at 11:55 PM, Daren Tan <[EMAIL PROTECTED]> wrote: > > My two matrices are roughly the sizes of m1 and m2. I tried using two apply > and cor.test to compute the correlation p.values. More than an hour, and the > codes are still running. Please help to make it more efficient. > > m1 <- matrix(rnorm(100000), ncol=100) > m2 <- matrix(rnorm(10000000), ncol=100) > > cor.pvalues <- apply(m1, 1, function(x) { apply(m2, 1, function(y) { > cor.test(x,y)$p.value }) }) > > ______________________________________________ > 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. > [[alternative HTML version deleted]] ______________________________________________ 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.