QR function

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QR function

Moritz Harteneck
Hi,

I am trying to make a QR decomposition of a fairly large matrix
(ca. 1584x252 real elements). However, I am not interested in the
rotation matrix q and I want to avoid it due to memory reasons. Does
anybody know how to do this?

Thanks

        Moritz

===========================================================================
Moritz Harteneck
SPD / EEE                    email: [hidden email]
University of Strathclyde    http://www.spd.eee.strath.ac.uk/~moritz
Glasgow G1 1XW, Scotland, U.K.
Tel: ++44-(0)141-548 2808           Fax: ++44-(0)141-552 2487


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QR function

John W. Eaton-6
On 14-Jul-1997, Moritz Harteneck <[hidden email]> wrote:

| I am trying to make a QR decomposition of a fairly large matrix
| (ca. 1584x252 real elements). However, I am not interested in the
| rotation matrix q and I want to avoid it due to memory reasons. Does
| anybody know how to do this?

With Octave 2.0.9, you can get R by running qr(x) and asking for only
one output:

  octave:1> help qr
  qr is a builtin function

    ...

  qr (X) alone returns the output of the LAPACK routine dgeqrf, such
  that R = triu (qr (X))


jwe