On Sep 7, 2012, at 17:16 , Tim Hesterberg wrote: > I suggest adding a 'pivot' argument to qr.R, to obtain columns in the > same order as the original x, so that > a <- qr(x) > qr.Q(a) %*% qr.R(a, pivot=TRUE) > returns x.
That would come spiraling down in flames the first time someone tried to use backsolve on it, wouldn't it? I mean, a major point of QR is that R is triangular; doesn't make much sense to permute the columns without retaining the pivoting permutation. -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
