Why can't we say s=(k+p) and accumulate (k+p) x (k+p) A*Omega rows at one time in the mapper and make sure we orthogonalize (k+p) rows of Q in one block (by running a stock QR)? That way orthogonalization of the final Q will be quaranteed (although columns of Q would be scaled at approx [m/(k+p)] )?
-Dmitriy On Mon, Apr 12, 2010 at 9:32 AM, Ted Dunning <ted.dunn...@gmail.com> wrote: > I will be attaching Dmitry's pdf. > > The basic difference is that I have gone back to a form closer to the > original paper to avoid computing an ill-conditioned SVD. > > Dmitriy also said: > > I guess at this point i don't understand the details of block QR. I guess > > i'll need to read up on block QR. I guess you could indeed go into a > little > > more into details of that qr() call and perhaps give geometry of > individual > > Yi, Qi and Ri matrices in step 1 ( i assume they should have s x (k+p), s > x > > ?, ? x (k+p) where s is the block height .) > > > > There isn't anything magic about the block QR and I doubt you will find any > information on the variant that I am using. The basic idea is just that I > am doing QR decompositions on row-wise blocks of A Omega. > > On Sun, Apr 11, 2010 at 10:54 PM, Ted Dunning <ted.dunn...@gmail.com> > wrote: > > > > > Can you attach that to the JIRA? Attachments are stripped from the > mailing > > list, I think. > > > > On Sun, Apr 11, 2010 at 9:55 PM, Dmitriy Lyubimov <dlie...@gmail.com > >wrote: > > > >> For reference, i am attaching summary of our previous discussion which > i > >> took liberty of slightly reworking. > > > > > > >
