[SciPy-dev] Current status of arpack.speigs.eigvals

Neilen Marais nmarais at sun.ac.za
Mon Nov 20 10:35:37 CST 2006


You'll find it works better for big matrices, since that's what the ARPACK
"tunables" were chosen for. Anyway, no, it's far from ready for primetime.
I've used it successfully to solve my problems though. Patches appreciated
(though wait for my update later today).

Regards
Neilen

On Mon, 20 Nov 2006 14:07:03 +0100, Nils Wagner wrote:

> Hi all,
> 
> I am wondering if arpack.speigs.eigvals is ready to compute eigenvalues.
> 
> a = random.rand(10,10)
> matvec = lambda x:dot(a,x)
> nev = 4
> ncv = 2*nev
> w1,v1 = arpack.speigs.eigvals(matvec,a.shape[0],nev=nev,ncv=ncv)
> 
> Traceback (most recent call last):
>   File "test_eigs.py", line 34, in ?
>     w1,v1 = arpack.speigs.eigvals(matvec,a.shape[0],nev=nev,ncv=ncv)
>   File
> "/usr/lib64/python2.4/site-packages/scipy/sandbox/arpack/speigs.py",
> line 71, in eigvals
>     if info != 0: raise "Hell" # Indicates some error during the
> Arnouldi iterations
> Hell
>  
> 
> Am I missing something ?
> 
> 
>        Nils

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but we've lost the magic
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