| Re: [eigen] ordering of eigenvalues of EigenSolver |
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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] ordering of eigenvalues of EigenSolver
- From: Gael Guennebaud <gael.guennebaud@xxxxxxxxx>
- Date: Tue, 22 Feb 2011 08:35:12 +0100
- Cc: Benoit Jacob <jacob.benoit.1@xxxxxxxxx>
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On Tue, Feb 22, 2011 at 1:18 AM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote:
>>
>> Furthermore, other eigenvalue decomposition libraries seem to order
>> eigenvalues, too. E.g., MatLab (based on ARPACK)
>
> Ah, I didn't know about Matlab.
actually MatLab does as us and Lapack do, for instance:
$ eig( diag([1 -1 2 -3 4]))'
ans =
-3 -1 1 2 4
Same for Octave or Scilab.
I don't see any reason to change for a convention that nobody follow
while our current behavior seems to be quite standard.
On the other hand we could allow for sorting capability such that user
can easily sort rows or column as they like.
gael