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Ublas : |
From: Karl Meerbergen (Karl.Meerbergen_at_[hidden])
Date: 2006-02-25 07:25:28
Hello,
ARPACK is good software. It is the number one reference for nonsymmetric
Krylov eigenvalue solvers.
I don't know the quality of UMFPACK.
What surprises me a bit is that you compute the eigenvalues of a generalized
eigenvalue problem from M^{-1} K. Does M have the same sparse structure as K?
Which eigenvalues are you looking for?
Usually, the spectral transformation (K-s*M)^{-1} M is used for
eigencomputations: it is more powerful than M^{-1} K for many applications
including structures, acoustics, chemical reactions ...
Karl
On Friday 24 February 2006 18:03, Sorkin Dmitri wrote:
> On Fri, 24 Feb 2006, Sorkin Dmitri wrote:
> > Hi.
> > I have some wrapper for ARPACK which also uses
> > bindings for UMFPACK. I didn't benchmark the
> > performance. It is pretty good for me.
> >
> > I attach the files that I use. There is lots
> > of "bad" code.The main class is
> > the "LAL_TypeEigDriverNonSym".
>
> "LAL" means that I actually solve the generalized
> eigen problem
> M*v*s = K*v
> in the form
> (L^-1)*K*(U^-1)*x=x*s
>
> where L*U = M (with umfpack)
> x = U*v
> "s" is the eigenvalue.
>
> I don't know whether the method is
> good or bad, I've just coded it.
>
> Dima.
>
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