Check out crossprod and the Matrix package (capitalized); there's also a discussion of their speed gains in the R newsletter that should turn up with a search and in the vignette as well.
-Gray On Monday, December 14, 2009, parkbomee <bbom...@hotmail.com> wrote: > > > > > > > Hi all, > > Is there a way to do a matrix multiplication in a faster way? > I am making a product of a matrix (composed of a lot of dummy variables) and > a vector, and is there any way to make it faster? > The simple X %*% y takes too long a time. > I know using sparse matrix would help, but don't know how to do it i R. > > > Thank you. > > > > _________________________________________________________________ > [[elided Hotmail spam]] > > [[alternative HTML version deleted]] > > ______________________________________________ > r-h...@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. > -- Gray Calhoun Assistant Professor of Economics Iowa State University ______________________________________________ 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.