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## Re: eigenvectors

 From: Eduardo Gallestey Subject: Re: eigenvectors Date: Thu, 10 Jun 1999 08:13:03 +1000

```address@hidden wrote:
>
> This may be a dumb question, forgive me, it's been too long.
>
> I have a real, square matrix Q and I need to factorize it as
>
>         Q = inv(X)*D*X
>
> where D is diagonal.  I think that this means that D contains the
> eigenvalues and X contains the eigenvectors of Q.  Is that right?  How do
> I get D and X from octave.  The function svd gives the "right and left"
> eigenvectors for any matrix.  I thought that for square matrices this
> would mean that it would return X but I was wrong.
>
> Sheepishly,
> Heber
>
>

Well, the problem is that not every matrix can be factorized in that
way. In general, what one has is the _Jordan_ form.  Furthermore, the
singular value decomposition (svd) is not directly related to your
problem. The situation is difficult to explain in just few lines, you
may want to consult a linear algebra textbook on the matter.

Regards,
Eduardo

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