[SciPy-user] I want to improve the speed of eig().

Nils Wagner nwagner@iam.uni-stuttgart...
Tue Jul 31 02:26:12 CDT 2007


HuiChang Moon wrote:
> Hi, users,
> I have a problem with calculating the eigenvalue problem using the eig().
> The array I want to calculate is about 5000*5000 but, the array is
> very sparse.
> At each row it has only 3 non-zero items, and the matrix is diagonal.
A diagonal matrix has only one entry per row. I guess you mean a
tridiagonal matrix ?
eig is restricted to dense arrays.
You may try arpack or lobpcg. It depends on the properties of your matrix
(symmetrie, definiteness, ...)
>>> from scipy.sandbox import lobpcg
>>> help (lobpcg)

>>> from scipy.sandbox import arpack
>>> help (arpack)

Can you send your matrix (in matrixmarket format) off-list ?

HTH
            Nils


> I have to solve eigenvalue problem, but it takes very long time.
> How can I do?
> I try to use sparse matix in Scipy, but eig() function doent' work
> with sparse_matrix.
> Please help me~!
> Thank you.
>
> -- 
> Nano SOI Process Lab.
> Hanyang University.
>
> Contacts;
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> +82-10-6455-7444
>
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