On Tue, Nov 22, 2011 at 4:27 PM, Martin Morgan <mtmor...@fhcrc.org> wrote: [...] > No need to Depend:. Use > > Imports: Matrix > > plus in the NAMESPACE file > > importFrom(Matrix, rowSums) > > Why do you not want to do this? Matrix is available for everyone, Imports: > doesn't influence the package search path. There is a cost associated with > loading the library in the first place, but...?
Not just loading, installing a package has a cost, too. Dependencies are bad, they might make my package fail, and I have no control over them. It's not just 'Matrix', I have this issue with other packages as well. Anyway, 'Imports: Matrix' is just a workaround I think. Or is the example in my initial mail expected to fail? Why is that? Why can I call some functions from 'Matrix' that way and why can't I call others? > I'm more into black-and-white -- it either needs Matrix or not; apparently > it does. It's a matter of opinion, I guess. I find it very annoying when I need to install a bunch of packages from which I don't use any code, just because some tiny bit of a package I need uses them. I would like to spare my users from this. [...] > In another message you mention > >> Matrix:::rowSums(W) > Error in callGeneric() : > 'callGeneric' must be called from a generic function or method > > but something else is going on -- you don't get to call methods directly; > you're getting Matrix::rowSums (it's exported, so no need for a :::, see > getNamespaceExports("Matrix")). Maybe traceback() after the error would be > insightful? Another poster suggested this, that's why I tried. It is clear that I should not call it directly. All I want to do is having a function like this: f <- function() { if (require(Matrix)) { res <- sparseMatrix(dims=c(5, 5), i=1:5, j=1:5, x=1:5) } else { res <- diag(1:5) } y <- rowSums(res) res / y } Setting the subjective bit, about depending or not, aside, is there really no solution for this? The code in the manual page examples work fine without importing the package and just loading it if needed and available. Why doesn't the code within the package? Thanks for the patience, Gabor > Martin > [...] -- Gabor Csardi <csa...@rmki.kfki.hu> MTA KFKI RMKI ______________________________________________ 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.