[petsc-users] Replacement for Euclid ?

[Matthew Knepley]

On Tue, Feb 7, 2017 at 7:53 AM, Michel Kern <michel.kern at inria.fr> wrote:

> Thanks Mat,
>
> according tot he hypre documentation, pilut is "no longer supported by the
> hypre team", as less efficient than Euclid, so I wouldn't consider an
> option. I wsa looking for a "natural" upgrade path.
>

I don't know of another ILU.

I have never understood the use of ILU. It is a fragile, not very scalable
algorithm which is soundly beaten in every
arena where we understand the problem. I also do not understand why it is
used as part of CPR. I can't believe that
is the best way to solve the problem. But maybe I do not understand.

  Thanks,

      Matt


> The problems we've looked at for the moment can be up to a few millions
> cells (that's the size of the pressure block, the saturation block is
> larger, but should be easier to solve). We're aiming for 10^6 cells, and
> 10^3 cores.
> Yes, direct methods deserve a second look !
>
> Michel
>
> ------------------------------
>
> On Tue, Feb 7, 2017 at 2:49 AM, Michel Kern <michel.kern at inria.fr> wrote:
>
>> I have a code that uses euclid for ILU preconditioning (as part of a
>> CPR-AMG preconditioner for a mulitphase flow solver). As noted in the
>> release notes, euclid is no longer supported starting from 3.6. What is the
>> recommended replacement ? Is block Jacobi plus a local solver an
>> alternative ?
>>
>
> There is pilut from Hypre.
>
> How big is the problem? Did you try sparse direct on it (SuperLU, MUMPS)?
>
>   Thanks,
>
>     Matt
>
>
>> Thanks
>> Michel
>>
>> --
>> Michel Kern
>> Centre de Recherche Inria de Paris,    Maison de la Simulation
>> 2 rue Simone Iff, bureau A413,            Digiteo Labs, bât 565, CEA
>> Saclay
>> 75012 Paris                                          91191 Gif-sur-Yvette
>> cedex
>> tel. : +33 (0)1 80 49 42 36 <+33%201%2080%2049%2042%2036>,
>>   tel. : +33 (0)1 69 08 58 32 <+33%201%2069%2008%2058%2032>
>>
>>
>>
>
>
> --
> What most experimenters take for granted before they begin their
> experiments is infinitely more interesting than any results to which their
> experiments lead.
> -- Norbert Wiener
>
>
>
>
> --
> Michel Kern
> Centre de recherche Inria de Paris,  Maison de la Simulation,
> 2 rue Simone Iff, bureau A413,       Digiteo Labs, bât. 565, CEA Saclay
> 75012 Paris                          91191 Gif-sur-Yvette Cedex
> tel. : +33 (0)1 80 49 42 36 <+33%201%2080%2049%2042%2036>,         tel. : +33
> (0)1 69 08 58 32 <+33%201%2069%2008%2058%2032>
>



-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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