[SciPy-user] generalized eigenvalue problem for sparse matrices

Matthieu Brucher matthieu.brucher@gmail....
Tue Apr 15 09:29:58 CDT 2008


Hi,

I've tested this function with a 2000x2000 array, and like Abhinav, I didn't
manage to find correct eigenvalues. Everything worked as expected with a
dense array with the same element with numpy.linalg.eig, but not with
Arpack...

Matthieu

2008/4/15, Nathan Bell <wnbell@gmail.com>:
>
> On Tue, Apr 15, 2008 at 1:48 AM, Abhinav Sarkar
> <abhinav.sarkar@gmail.com> wrote:
> >  I tried the eigenvalue problem solver provided for the dense matrices
> at
> >  scipy.linalg.eig and it gives the same result as the MATLAB functin
> eig. Then
> >  why is scipy.sparse.linalg.eigen.arpack.speigs.ARPACK_gen_eigs giving
> different
> >  result? Please help me out.
>
>
> Have you also tried eigs() in MATLAB?  I'm not sure what happens when
> you call eig() with a sparse matrix.
>
> As Neilen said, this isn't a good test for ARPACK.  Try setting the
> 'tol' parameter to something smaller.
>
>
> --
> Nathan Bell wnbell@gmail.com
> http://graphics.cs.uiuc.edu/~wnbell/
>
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>



-- 
French PhD student
Website : http://matthieu-brucher.developpez.com/
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