On 9/7/12 2:42 PM, "peter dalgaard" <pda...@gmail.com> wrote:
> >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. As I understand Tim's proposal, the pivot argument defaults to FALSE, so the new behavior would only be activated at the user's request. -Greg -- Gregory Warnes, Ph.D. Sr. Expert Modeler Modeling and Simulation CA Phone: +1 617 871-8498 gregory.war...@novartis.com ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
