[Numpy-discussion] numpy.linalg.eig

Tommy Carstensen e-alerts at proteinkemi.dk
Tue Sep 16 12:33:07 EDT 2008


Dear Robert Kern,

Thanks for your interest in helping me.

Previously I used LinearAlgebra.Heigenvectors. I should have switched to
numpy.linalg.eigh instead of numpy.linalg.eig, since I work with Hermitian
(non-complex and symmetric) matrices.

Kind regards,
Tommy

-----Original Message-----
From: numpy-discussion-bounces at scipy.org
[mailto:numpy-discussion-bounces at scipy.org] On Behalf Of Robert Kern
Sent: 15 September 2008 17:39
To: Discussion of Numerical Python
Subject: Re: [Numpy-discussion] numpy.linalg.eig

On Mon, Sep 15, 2008 at 09:50, Tommy Carstensen <e-alerts at proteinkemi.dk>
wrote:
> To the numpy mailing list,
>
> Previously I used python2.3 and the module LinearAlgebra for matrix
> diagonalization. I recently upgraded to python2.5 and I am now using
> numpy.linalg.eig for matrix diagonalization. This is approximately 3 times
> slower than previously. I am using the same work station as previously and
> it has all lapack libraries installed to my knowledge. Does anyone have an
> explanation as to why I am experiencing the reduced speed of calculation?

Although you have the same LAPACK libraries installed, Numeric and
numpy may have been built differently, and numpy may not be using the
same libraries. Can you check?

> This is my first post to this mailing list, so I hope this mail complies
> with the mailing list standards.

Yes, certainly.

-- 
Robert Kern

"I have come to believe that the whole world is an enigma, a harmless
enigma that is made terrible by our own mad attempt to interpret it as
though it had an underlying truth."
 -- Umberto Eco
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