From help-request at octave dot org Sat Apr 15 15:18:02 2006
Subject: chol?
From: Vic Norton <vic at norton dot name>
To: Octave Help <help at octave dot org>
Date: Sat, 15 Apr 2006 16:16:22 -0400

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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