[petsc-dev] plans for preconditioners for SeqSELL

[Stefano Zampini]

This is the branch I'm currently working on
https://bitbucket.org/petsc/petsc/branch/stefano_zampini/feature-factor-sell
So far, it provides support for MUMPS and SUPERLU

2018-02-12 19:25 GMT+03:00 Stefano Zampini <stefano.zampini at gmail.com>:

> Barry,
>
> for sure Amat,Pmat is the right approach; however, with complicated user
> codes, we are not always in control of having a different Jacobian matrix.
> Since Mat*SELL does not currently support any preconditioning except PCSOR
> and PCJACOBI, we ask the user to put codes like
>
> if (type is SELL)
>  create two matrices (and maybe modify the code in many other parts)
> else
>   ok with the previous code
>
> Just my two cents.
>
>
> 2018-02-12 19:10 GMT+03:00 Smith, Barry F. <bsmith at mcs.anl.gov>:
>
>>
>>
>> > On Feb 12, 2018, at 9:59 AM, Stefano Zampini <stefano.zampini at gmail.com>
>> wrote:
>> >
>> > FYI, I just checked and MatSOR_*SELL does not use any vectorized
>> instruction.
>> > Why just not converting to SeqAIJ, factor and then use the AIJ
>> implementation for MatSolve for the moment?
>>
>>   Why not use the mat, pmat feature of the solvers to pass in both
>> matrices and have the solvers handle using two formats simultaneously
>> instead of burdening the MatSELL code with tons of special code for
>> automatically converting to AIJ for solvers etc?
>>
>>
>> >
>> > 2018-02-12 18:06 GMT+03:00 Stefano Zampini <stefano.zampini at gmail.com>:
>> >
>> >
>> > 2018-02-12 17:36 GMT+03:00 Jed Brown <jed at jedbrown.org>:
>> > Karl Rupp <rupp at iue.tuwien.ac.at> writes:
>> >
>> > > Hi Stefano,
>> > >
>> > >> Is there any plan to write code for native ILU/ICC etc for SeqSELL,
>> at least to have BJACOBI in parallel?
>> > >
>> > > (imho) ILU/ICC is a pain to do with SeqSELL. Point-Jacobi should be
>> > > possible, yes. SELL is really just tailored to MatMults and a pain for
>> > > anything that is not very similar to a MatMult...
>> >
>> > There is already MatSOR_*SELL.  MatSolve_SeqSELL wouldn't be any harder.
>> > I think it would be acceptable to convert to SeqAIJ, factor, and convert
>> > the factors back to SELL.
>> >
>> > Yes, this was my idea. Today I have started coding something. I'll push
>> the branch whenever I have anything working
>> >
>> >
>> >
>> > --
>> > Stefano
>> >
>> >
>> >
>> > --
>> > Stefano
>>
>>
>
>
> --
> Stefano
>



-- 
Stefano
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