Thanks for the input Peter. I suppose I never looked at lm() to see how it was used there. Given that though, do you see any reason then to not create an S3/S4 method if different methods are used for different functions? I'm just looking for some design guidance from the community here before I just implement something that may cause more confusion.
Regards, Charles On Tue, Aug 2, 2016 at 4:34 PM, Peter Dalgaard <pda...@gmail.com> wrote: > Not strictly what you're asking, but at some point it may be important to > note that the "QR" method used by lm() and friends (notably anova() and > aov()) actually relies on successive orthogonalization. This does yield a > QR decomposition but the reverse is not true. A generic X=QR decomposition > does orthogonalize, but it does not necessarily hold that the first k > columns of Q spans the same subspace as the first k columns of X. LINPACK's > QR happens to be implemented as successive orthogonalization, but LAPACK's > is not, so only the former is usable with lm(). > > So, I suppose what I am getting at is that not even lm() uses qr(), it > calls LINPACK directly. > > -pd > > > > On 02 Aug 2016, at 21:17 , Charles Determan <cdeterma...@gmail.com> > wrote: > > > > Hello, > > > > I am currently working on an implementation of QR decomposition > (leveraging > > a C++ library via Rcpp). Naturally I would like to have the R syntax as > > similar as possible to base R 'qr' function. Given the class structure > of > > my package my instinct was to export an S4/S3 method. > > > > However, the QR decomposition doesn't store the final QR matrix in the > same > > format as base R via LINPACK, nor does it return 'qraux', 'rank' or > 'pivot' > > objects but instead a 'betas' object. The final 'R' and 'Q' matrices are > > in fact identical to those ultimately returned by qr.R or qr.Q. > > > > So my question is, given these differences, should I just create a > > different function name or would creating a qr.myclass dispatch be > > acceptable (whether S3 or S4)? I would prefer the latter as I would like > > the classes to potentially take advantage of previously written code > using > > 'qr'. > > > > Thanks, > > Charles > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-package-devel@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-package-devel > > [[alternative HTML version deleted]] ______________________________________________ R-package-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-package-devel
