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Subject: Re: Help!!! Eigenvalue program for frequency dependent matrix
Date: Fri, 11 Jul 2008 21:08:02 +0000 (UTC)
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"Miroslav Balda" <miroslav.nospam@balda.cz> wrote in message
<g53alh$2tc$1@fred.mathworks.com>...
> "Miroslav Balda" <balda.nospam@cdm.it.cas.cz> wrote in
> message <g51igi$8g1$1@fred.mathworks.com>...
> :
> SNIP
> :
> 
> > You wanted to solve the eigenvalue problem for omega as a
> > function of S. It is possible to solve it in iterations for
> > a single eigenvalue s_k, if you reguire that, say, omega=
> > real(s_k). Then, you may use the MATLAB  function fzero
> > applied to the difference  omega-real(s_k).
> 
> Sorry, there should be  omega = imag(s_k).
> 
> Mira
> 

Hi Mira,

Thanks for your response. I had implemented something
similar before posting it on the newsgroup. 

Here is what I was doing:

1. Assume a certain omega.
2. Find K for this omega
3. Find eigenvalues
4. Check is the eigenvalue is the same as the omega assumed
in step-1. 
5. If yes, this omega is an eigenvalue. Store the freuqency
and eigenvector.

There are "numerical" problems with this approach though. I
know that the frequency will lie between 0-10,000 Hz. Now,
your ability to predict the eigenvalue depends upon how good
your approximation in (1) is. This, in my opinion, is not
the most elegant approach.

I tried vector iteration approaches but they can only give
the first and last eigenvalues.

I appreciate your inputs and thank you again.