Try this: matrix(apply(u, 1, tcrossprod), nr = nrow(u)*ncol(u), byrow = T)
On Mon, Jan 19, 2009 at 3:39 PM, Stephan Lindner <lindn...@umich.edu> wrote: > Dear all, > > > I have a simple question which I unfortunately do not seem to be able > to solve myself. I have a (NxK) matrix and want to generate a new > matrix by multiplying each row with itself such that the new matrix > has dimension ((N*K)xK) (or better, generate an array with dimension > (K,K,N)). I tried apply, but that did not work. Any suggestions? > > Thanks! > > > Stephan > > > > ## Here is a simple example: > > u <- matrix(c(1,2,3,4,5,6,7,8,9,10),nrow=2) > > ## What I want to obtain > > u[1,]%*%t(u[1,]) > u[2,]%*%t(u[2,]) > > ## stacked together --> 10x5 matrix > > > ## This does not work > > sq <- function(x)x%*%t(x) > apply(u,1,function(y)sq(y)) > > > > > > > -- > ----------------------- > Stephan Lindner > University of Michigan > > ______________________________________________ > 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. > -- Henrique Dallazuanna Curitiba-Paraná-Brasil 25° 25' 40" S 49° 16' 22" O [[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.
