great, thanks! jc
On Wed, Dec 16, 2009 at 20:55, William Dunlap <wdun...@tibco.com> wrote: > > -----Original Message----- > > From: r-help-boun...@r-project.org > > [mailto:r-help-boun...@r-project.org] On Behalf Of > > Jean-Christophe Domenge > > Sent: Wednesday, December 16, 2009 11:48 AM > > To: r-help > > Subject: [R] number of observations used in cor when > > use="pairwise.obs" > > > > Dear R gurus, > > to compute the correlation matrix of "n" variables with > > "n_obs" observations > > each, > > possibly including NA, I use cor(M, use="pairwise.obs") > > where m is a "n" x "nobs" matrix. > > > > Now I want to know the number of observations actually used in this > > computation, > > namely for each pair of columns in M, say pair (i,j), I want > > to compute > > sum( !is.na(M[,i]) & !is.na(M[,j]) ). > > I can think of several ways of constructing all pairs (i,j) > > with i<j, then > > computing the sum > > above, but for n=2000 and nobs=700 the computation time is > > prohibitive. > > Try > crossprod(!is.na(M)) > > Bill Dunlap > Spotfire, TIBCO Software > wdunlap tibco.com > > > > > Is there an efficient way to solve this? > > > > Many thanks, > > > > jc > > > > [[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. > > > [[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.
