[petsc-users] Preconditioners for a FEM model

[jifeng zhao]

Hi Murat,

Yes, that sounds great. I would like to have a try. Would you let me know
how to use it on top of SLEPC and PETSC in more details?

Cheers,
Jifeng Zhao


On Wed, Jul 2, 2014 at 9:41 PM, murat keçeli <keceli at gmail.com> wrote:

> Hi Jifeng,
>
> I think your application is suitable for the SIPs method, see attached
> paper.  We have improved it recently, so that it can handle very
> large (500k by 500k with more than 3.e7 nonzeros) sparse matrices.Current
> version of SIPs is basically adding a second layer of parallelism on top of
> SLEPc's shift and invert method. Let me or Hong Zhang (cc, the developer of
> SIPs) know, if you would like to give it a try.
>
> Murat Keceli
>
>
> On Wed, Jul 2, 2014 at 4:46 PM, jifeng zhao <
> jifengzhao2015 at u.northwestern.edu> wrote:
>
>> Hello all,
>>
>> I am working on solving a generalized eigenvalue problem with SLEPC and
>> PETSC.
>>
>> *K* x = lamda *M* x
>>
>> I attached the sparsity pattern of matrix *M* (*K* is the same). It is a
>> FEM model. It is so sparse is because of constraints.
>>
>> I have tried two things:
>>
>> 1. Krylov-Schur and exact shift-and-invert (I will try MUMPS in future).
>> It works. But I am worrying that it is less parrallelable, when the problem
>> contains millions of degree of freedom.
>>
>> 2. JD with Jacobi preconditioner. It could work, but a lot of tuning
>> needs to be done in terms of RTOL, max_iteration_number. And sometimes I
>> suffer from a stagnated solution, and can't obtain accurate result.
>>
>> Does anybody know that for my specific case of matrix sparsity, is there
>> any thing I can do to speed up my direct solver (Krylov-Schur)?
>>
>> Is there any recommended preconditioners I could try on, for the case of
>> JD? There are a lot of preconditioners in HYPRE library.
>>
>> Thank you in advance!
>> [image: Inline image 1]
>>  --
>> Jifeng Zhao
>> PhD candidate at Northwestern University, US
>> Theoretical and Applied Mechanics Program
>>
>
>


-- 
Jifeng Zhao
PhD candidate at Northwestern University, US
Theoretical and Applied Mechanics Program
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