> On Feb 12, 2018, at 10:25 AM, Stefano Zampini <stefano.zamp...@gmail.com> 
> wrote:
> 
> 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

   I don't disagree with what you are saying and am not opposed to the proposed 
work.

   Perhaps we need to do a better job with making the mat,pmat approach simpler 
or better documented so more people use it naturally in their applications.

    Barry

> 
> Just my two cents.
> 
> 
> 2018-02-12 19:10 GMT+03:00 Smith, Barry F. <bsm...@mcs.anl.gov>:
> 
> 
> > On Feb 12, 2018, at 9:59 AM, Stefano Zampini <stefano.zamp...@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.zamp...@gmail.com>:
> >
> >
> > 2018-02-12 17:36 GMT+03:00 Jed Brown <j...@jedbrown.org>:
> > Karl Rupp <r...@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

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