Re: chol?

[dastew]

Here is what I get

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octave:1> C = [36 24; 24 25];
octave:2> C
C =

  36  24
  24  25

octave:3> 
octave:3> chol(C)
ans =

  6  4
  0  3
Upper Triangular


Doug Stewart




> 
> From: Vic Norton <address@hidden>
> Date: 2006/04/15 Sat PM 04:16:22 EST
> To: Octave Help <address@hidden>
> Subject: chol?
> 
> I had thought Octave, version 2.1.73, was working fine on my iMac G5,
> but now I'm not so sure. Here's my problem.
> 
> I start with the matrix
>    octave> C = [36 24; 24 25];
> and do
>    octave> chol(C);
> After waiting for a while I get
>    panic: Bus error -- stopping myself...
>    attempting to save variables to `octave-core'...
>    save to `octave-core' complete
>    Bus error
>    vic$
> 
> To tell you the truth I'm not sure what the Cholesky factor of C is
> supposed to be. I do know that C = R' * R where
>    R = [0 3; 6 4].
> I have no problem computing another R that does this job:
>    octave> C = [36 24; 24 25];
>    octave> [U, S, V] = svd(C);
>    octave> R = sqrt(S) * V';
> Now
>    R = [
>           -5.8067  -4.6265
>           -1.5108   1.8962
>        ]
> and C = R' * R for this R as well. But R = chol(C) simply doesn't work
> for me.
> 
> Is anybody else having any problems with "chol" or is it just my screwed
> up system?
> 
> Regards,
> 
> Vic
> 
> 
> 
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Octave is freely available under the terms of the GNU GPL.

Octave's home on the web:  http://www.octave.org
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