In the "old days", one way of speeding up matrix calculations was to drop the dimnames of the matrices prior to the calculations, i.e., dimnames(X) <- NULL. I distinctly remember that this could have a great impact at least in Splus 3.x (under UNIX/Linux).
I just did a small, informal test of this with a couple of functions I use to fit plsr models, in R 2.3.0 (Linux). It didn't seem to have any effect at all (the functions actually ran a tiny bit slower, probably due to the "dimnames(X) <- NULL" command). Is the "general rule-of-thumb" with current R versions that the overhead of keeping the dimnames through calculations is negligible? -- Bjørn-Helge Mevik ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
