yes, I think that would be useful. G
On Tue, Apr 1, 2014 at 2:40 PM, Stefan Karpinski <[email protected]> wrote: > Should we maybe provide an orth function that does this for you? > > > On Tue, Apr 1, 2014 at 2:39 PM, Douglas Bates <[email protected]> wrote: >> >> On Monday, March 31, 2014 8:56:45 PM UTC-5, Gustavo Lacerda wrote: >>> >>> Do we have something like Matlab's 'orth'? i.e. given a matrix M, find >>> an orthonormal basis of the column-space of M? >> >> >> If M has full column rank the simplest method is >> >> orth(M) = qr(M)[1] >> >> or, equivalently, >> >> qrfact(M)[:Q] >> >> although this returns an object of type QRCompactWYQ. >> >> If M can be singular then you are probably better off using svdfact and >> taking the columns of the [:U] matrix corresponding to non-zero values in >> the [:S] vector. > >
