On 10/3/2006 4:59 PM, roger bos wrote: > Dear useRs, > > Trying to replace the diagonal of a matrix is not working for me. I > want a matrix with .6 on the diag and .4 elsewhere. The following > code looks like it should work--when I lookk at mps and idx they look > how I want them too--but it only replaces the first element, not each > element on the diagonal. > > mps <- matrix(rep(.4, 3*3), nrow=n, byrow=TRUE) > idx <- diag(3) > mps > idx > mps[idx] <- rep(.6,3) > > I also tried something along the lines of diag(mps=.6, ...) but it > didn't know what mps was.
Matrix indexing can use a two column matrix, giving row and column numbers. So you could get what you want by mps[cbind(1:n,1:n)] <- 0.6 ______________________________________________ [email protected] 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.
