Fwd: RE: QRDecomposition
- Subject: Fwd: RE: QRDecomposition
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- Date: Sun, 29 Jul 2007 22:01:04 -0400
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Sender: "Cleve Moler" <Cleve.Moler@mathworks.com>
Subject: RE: QRDecomposition
You are right -- the Linstats toolbox on MATLAB Central does make use of
QR with column pivoting. As I said earlier, including column pivoting
in our Java code is nontrivial. You might want to consider calling
MATLAB or LAPACK from Java instead.
From: firstname.lastname@example.org [mailto:email@example.com] On Behalf Of Sione
Sent: Thursday, July 26, 2007 4:11 PM
To: Multiple recipients of list
Subject: Re: QRDecomposition
There are a few Matlab functions from some toolboxes available for
free download on the internet that I want to port to Java using JAMA,
which require the use of :
[Q,R,E] = QR(A) ;
One such function is "solve.m" which is called by another function
"manova.m" where I want to port into Java from the "Linstats" toolbox ,
and is available from Matlab Central.
Cleve Moler wrote:
> 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
> 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
> "E" , the permutation matrix.
> Any help would be appreciated.
----- End forwarded message -----
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