[SciPy-user] Eigenvalues and eigenvectors

[Nils Wagner]

David Grant wrote:
>
>
> On 7/11/06, *Johannes Loehnert* <a.u.r.e.l.i.a.n at gmx.net 
> <mailto:a.u.r.e.l.i.a.n at gmx.net>> wrote:
>
>     Hi,
>
>     > This probably isn't what you meant, but...
>     > last I checked there was no function in Scipy that would let you
>     get just
>     > *some* eigenvalues and eigenvectors.  eig() gets you *all*
>     eigenvals/vecs
>     > whether you want them or not.   Which is really a bad idea if
>     you're trying
>     > to do some sort of eigenvector-based
>     compression/dimension-reduction on a
>     > 5000 dimensional dataset.
>
>     scipy.linalg.eig_banded can be used to obtain a subset of
>     eigenvectors (by
>     giving limits for the eigenvalues or by specifying an index
>     range). However
>     it is only applicable to symmetric and hermitian matrices (preferably
>     band-limited, of course). Internally it wraps the lapack routines
>     dsbevx /
>     zhbevx.
>
>     I do not know if it is already contained in the latest scipy
>     release, maybe
>     you need to build from svn.
>
>
> Thanks. It doesn't look like it is in scipy-0.4.9
>
> -- 
> David Grant
> Please Note my new email address: davidgrant at gmail.com 
> <mailto:davidgrant at gmail.com>
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http://projects.scipy.org/scipy/scipy/changeset/2030
 
Nils