[Fwd: RE: QRDecomposition]

[Ron Boisvert <boisvert@nist.gov>]

Sender: "Cleve Moler" <Cleve.Moler@mathworks.com>
Subject: RE: QRDecomposition


Hi, Sione --

Including column permutations in the QR decomposition involves major
modifications to the code.  Why do you think you need it?

  -- Cleve

-----Original Message-----
From: jama@NIST.GOV [mailto:jama@NIST.GOV] On Behalf Of Sione
Sent: Wednesday, April 25, 2007 8:09 AM
To: Multiple recipients of list
Subject: QRDecomposition

Hi All,

Does anyone know of how to modify the  QRDecomposition  class so   to be

able to do what  Matlab  "qr"  command does,  such as the following 
description in Matlab.

[Q,R,E] = QR(A) produces unitary Q, upper triangular R and a
permutation matrix E so that A*E = Q*R. The column permutation E is
chosen so that ABS(DIAG(R)) is decreasing.

I want to modify the  QRDecomposition  class so that it also calculates

"E" , the permutation matrix.

Any help would be appreciated.

Cheers,
Sione.