Well, it would be possible to set something up to select out just the right pairs each time, but on my system the following
a <- matrix(rnorm(40 * 732), 40) b <- matrix(rnorm(40 * 1230), 40) system.time(cor(a,b,method = "pearson")) takes about a tenth of a second so any more elective approach will probably loose in the interpreter time needed for all the subsetting. The slowest calculation of this sort (Kendall correlation) takes about 30 seconds. In short, just do cor(A,B, method = "pearson") and then subset from the overall correlation matrix. Michael On Thu, Mar 8, 2012 at 6:57 PM, A Ezhil <ezhi...@yahoo.com> wrote: > Dear All, > I have two matrices A (40 x 732) and B (40 x 1230) and would like to > calculate correlation between them. I can use: cor(A,B, method="pearson") to > calculate correlation between all possible pairs. But the issue is that there > is one-many specific mappings between A and B and I just need to calculate > correlations for those pairs (not all). Some variables in A (proteins, say > p1) have more than 3 (or 2 or 1) corresponding mapping in B (mRNA, say, > m1,m2,m3) and I would like calculate correlations between p1-m1, p1-m2, and > p1-m3 and then for the second variable p2 etc. > I have the mapping information in another file (annotation file). Could you > please suggest me how to do that? > Thanks in advance. > Kind regards,Ezhil > [[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. > ______________________________________________ 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.
