[Numpy-discussion] Eigenvalues did not converge
Rick Muller
I've seen this before (though not for several years), and what I normally do is to build lapack with -O0. This trick did not work in the current instance. Does anyone have any tricks to getting eigh to work?
Other weird things that I've noticed about this case: I can compute the eigenvalues using eigvals and eigvalsh, and can compute the eigenvals/vecs using eig(). The matrix is real symmetric, and I've tested that it's symmetric enough by forcibly symmetrizing it.
Thanks in advance for any help you can offer.
--
Rick Muller
rpmu...@gmail.com
505-750-7557
Charanpal Dhanjal
numpy.linalg.svd a few weeks ago. I'm not sure I can help but I wonder
if you compiled numpy with ATLAS/MKL support (try numpy.show_config())
and whether it made a difference? Also what is the condition number and
Frobenius norm of the matrix in question?
Charanpal
On Mon, 29 Aug 2011 08:56:31 -0600, Rick Muller wrote:
> Im bumping into the old "Eigenvalues did not converge" error using
> numpy.linalg.eigh() on several different linux builds of numpy
> (1.4.1). The matrix is 166x166. I can compute the eigenvalues on a
> Macintosh build of numpy, and I can confirm that there arent
> degenerate eigenvalues, and that the matrix appears to be negative
> definite.
>
> Ive seen this before (though not for several years), and what I
> normally do is to build lapack with -O0. This trick did not work in
> the current instance. Does anyone have any tricks to getting eigh to
> work?
>
> Other weird things that Ive noticed about this case: I can compute
> the eigenvalues using eigvals and eigvalsh, and can compute the
> eigenvals/vecs using eig(). The matrix is real symmetric, and Ive
> tested that its symmetric enough by forcibly symmetrizing it.
>
> Thanks in advance for any help you can offer.
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Paul Anton Letnes
Paul
Rick Muller
Charanpal Dhanjal
BLAS/LAPACK libraries currently in use. Here is a good place to start:
http://www.scipy.org/Installing_SciPy/Linux.
Charanpal
On Thu, 1 Sep 2011 12:20:46 -0600, Rick Muller wrote:
> Yes, as I pointed out, the problem does run on the Macintosh systems.
> But Id like to be able to run these on our linux supercomputers.
> Surely this is possible, right?
>
> On Mon, Aug 29, 2011 at 9:31 AM, Paul Anton Letnes wrote:
>
>> I recently got into trouble with these calculations (although I used
>> scipy). I actually got segfaults and "bus errors". The solution for
>> me was to not link against ATLAS, but rather link against Apples
>> blas/lapack libraries. That got everything working again. I would
>> suggest trying to install against something other than ATLAS and see
>> if that helps (or, more generally, determining which blas/lapack you
>> are linking against, and try something else).
>>
>> Paul
>>
>> On 29. aug. 2011, at 16.21, Charanpal Dhanjal wrote:
>>
>> > I posted a similar question about the non-convergence of
>> > numpy.linalg.svd a few weeks ago. Im not sure I can help but I
>> > NumPy-Di...@scipy.org [1]
>> > http://mail.scipy.org/mailman/listinfo/numpy-discussion [2]
>>
>> _______________________________________________
>> NumPy-Discussion mailing list
>> NumPy-Di...@scipy.org [3]
>> http://mail.scipy.org/mailman/listinfo/numpy-discussion [4]
>
> --
> Rick Muller
> rpmu...@gmail.com [6]
> 505-750-7557
>
>
>
> Links:
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Paul Anton Letnes
ymmv,
Paul.