From help-request at octave dot org Sat Apr 15 15:31:05 2006 Subject: Re: chol? From: Marius Schamschula To: Vic Norton Cc: Octave Help Date: Sat, 15 Apr 2006 15:29:28 -0500 --Apple-Mail-2--677956293 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Vic, Is this the port from hpc.sf.net, or did you compile from source? I have yet to get a working build of octave 2.1.73 on the Mac. On Apr 15, 2006, at 3:16 PM, Vic Norton wrote: > 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 Marius -- Marius Schamschula Webmaster The Huntsville Macintosh Users Group www.hmug.org webmaster at hmug dot org marius at schamschula dot com --Apple-Mail-2--677956293 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 Vic,

Is this the port from = hpc.sf.net, or did you compile from source?

I have yet to get a working = build of octave 2.1.73 on the Mac.

On Apr 15, = 2006, at 3:16 PM, Vic Norton wrote:

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
=A0=A0 octave> C =3D [36 24; = 24 25];
and do
=A0=A0 = octave> chol(C);
After waiting = for a while I get
=A0=A0 panic: Bus error -- = stopping myself...
=A0=A0 attempting to save = variables to `octave-core'...
=A0=A0 save to `octave-core' = complete
=A0=A0 Bus error
=A0=A0 = 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 = =3D R' * R where
=A0=A0 R =3D [0 3; 6 = 4].
I have no problem computing = another R that does this job:
=A0=A0 octave> C =3D [36 24; = 24 25];
=A0=A0 octave> [U, S, V] =3D = svd(C);
=A0=A0 octave> R =3D sqrt(S) * = V';
Now
=A0=A0 R =3D [
=A0 =A0 =A0 =A0 = =A0 -5.8067=A0 = -4.6265
=A0 =A0 =A0 =A0 =A0 -1.5108 =A0 1.8962
=A0=A0 =A0 =A0 = ]
and C =3D R' * R for this R as = well. But R =3D chol(C) simply doesn't work
for = me.

Is anybody else having any problems with "chol" or = is it just my screwed
up system?


Vic


Marius

--

Marius Schamschula =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0= =A0 =A0 =A0 =A0 =A0 =A0 =A0 Webmaster


=A0 =A0 =A0 =A0 The Huntsville Macintosh Users = Group

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 www.hmug.org


webmaster at hmug dot org=A0 =A0 marius at schamschula = dot com


=

= --Apple-Mail-2--677956293-- ------------------------------------------------------------- Octave is freely available under the terms of the GNU GPL. Octave's home on the web: http://www.octave.org How to fund new projects: http://www.octave.org/funding.html Subscription information: http://www.octave.org/archive.html -------------------------------------------------------------