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Re: qz
From: |
Stefan van der Walt |
Subject: |
Re: qz |
Date: |
Thu, 15 Jul 2004 23:17:54 +0200 |
User-agent: |
Mutt/1.5.6+20040523i |
Thanks, Quentin. I see MATLAB and Octave differs in this regard.
Why is MATLAB's answers numerically so different to that of Octave?
Is the QZ factorisation non-unique?
I am happy to see that the eigenvalues and -vectors are the same,
though.
Regards
Stefan
On Thu, Jul 15, 2004 at 03:02:50PM -0500, Quentin Spencer wrote:
> >octave:5> a = rand(3,3); b = rand(3,3); [AA, BB, Q, Z, V, W] =
> >qz(a,b); Q*a*Z - AA, Q*b*Z - BB
> >ans =
> >
> > -0.506316 0.133307 1.509299
> > -0.425943 -0.168888 -1.856508
> > 0.203352 -0.028521 -0.327870
> >
> >ans =
> >
> > -0.377653 -0.108805 1.424638
> > 0.274852 -0.178300 -0.189498
> > 0.098925 0.051424 -0.448613
> >
> >If I understand correctly, the answers should be much closer to
> >zero(3,3)?
> >
> >
> You are close. Replace Q with Q', and I get matrices with values on the
> order of 1E-16.
>
> -Quentin
>
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-------------------------------------------------------------
- qz, Stefan van der Walt, 2004/07/15
- Re: qz, Quentin Spencer, 2004/07/15
- Re: qz,
Stefan van der Walt <=