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From: Rune Allnor <allnor@tele.ntnu.no>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Help!!! Eigenvalue program for frequency dependent matrix
Date: Sat, 12 Jul 2008 01:35:15 -0700 (PDT)
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On 11 Jul, 23:08, "Yogesh " <ya...@trashmail.net> wrote:
> "Miroslav Balda" <miroslav.nos...@balda.cz> wrote in message
> Here is what I was doing:
>
> 1. Assume a certain omega.
> 2. Find K for this omega

Depending on exactly what you do, this will be the wrong answer.
If this is a wave propagation problem (the terminology suggests
it is) then the eigenvalues you are looking for are pairs of
frequencies and wavenumbers (w,k) that make the boundary
conditions in the physical environment match.

For instance, if you work with acoustic waves in a perfect
underwater waveguide, the reflection coefficient at the
water surface is -1 and at the bottom +1.

So you want to find the pair(s) (w,k) that meets the
boundary conditions *both* at the surface and at the
bottom. Depending on exactly what you look for, there may
be any number of solutions.

Check out the book 'Computational Ocean Acoustics' by
Jensen & al to find a number of ways to find eigenvalues
in wave propagation problems.

Rune