[SciPy-user] Using umfpack to calculate a incomplete LU factorisation (ILU)

Nils Wagner nwagner@iam.uni-stuttgart...
Thu Mar 8 07:19:54 CST 2007


Robert Cimrman wrote:
> Neilen Marais wrote:
>   
>> I'm trying to get an incomplete LU factorisation of a sparse matrix using
>> scipy.linsolve.splu. It's using umfpack as far as I can tell. I'm telling
>> it to drop elements using the drop_tol keyword argument, though it seems
>> to be having no effect:
>>     
>
> Just one correction: linsolve.splu uses SuperLU function *gstrf, so if
> the threshold does not work, the problem is there...
>
> Otherwise you can get LU factors with UmfpackContext.lu, but those are
> always complete.
>
> cheers,
> r.
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>   
Just out of interest

Is there something comparable with

sigma_solve = linsolve.splu(A - sigma*B).solve

available in UMFPACK ?

Nils
 


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