[petsc-users] Regarding ksp ex42 - Citations

[Matthew Knepley]

On Mon, Jul 18, 2016 at 12:59 AM, domenico lahaye <domenico_lahaye at yahoo.com
> wrote:

> Thanks for all the pointers.
>
> I am happy to switch to ksp/examples/tutorials/ex25.c in a first instance
> as you suggest.
>
>     I am still stuck with the same issue as before though. I am trying to
> extract the hierarchy
>     of coarser grid matrices and the intergrid transfer operators from the
> DMDA data structure. I would
>     like to modify these operators and define a multigrid cycle with the
> modified operators.
>
>     Given A^h (Helmholtz) and M^h (shifted Laplace), I would like to
> define a multigrid cycle involving
>     both A^H and M^H. Can I rely on the multilevel DMDA structure to
> construct A^H and M^H for me
>     in a set-up phase, plug them into a user-defined context, and plug
> them back out in a solve phase?
>

If you are not using -pc_mg_galerkin, then the FormJacobian is called
separately on each level to rediscretize the operator.
The only thing that changes is the DMDA that is passed to the call. If you
need more information, there are hooks to
attach different contexts to each MG level. Do you need this?

  Thanks,

     Matt


> Thanks, Domenico.
>
>
> ------------------------------
> *From:* Matthew Knepley <knepley at gmail.com>
> *To:* Barry Smith <bsmith at mcs.anl.gov>
> *Cc:* domenico lahaye <domenico_lahaye at yahoo.com>; "
> petsc-users at mcs.anl.gov" <petsc-users at mcs.anl.gov>
> *Sent:* Sunday, July 17, 2016 2:29 PM
> *Subject:* Re: [petsc-users] Regarding ksp ex42 - Citations
>
> On Sat, Jul 16, 2016 at 10:11 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
>
> > On Jul 14, 2016, at 12:21 PM, domenico lahaye <domenico_lahaye at yahoo.com>
> wrote:
> >
> > Dear PETSc team,
> >
> > 1) I am looking into ks/examples/tutorials/ex42.c I am still new to the
> DMDA structure
> >     and likely not giving it as much time as it deserves. However, I do
> not see immediately
> >     what function is responsible for calling PCMGSetSmoother and
> PCMGSetResidual.
> >
> >      I tried to call PCMGGetCoarseSolve(pc, &kcpc) and subsequently
> >      KSPGetOperators (kspc, ... ) to check how the coarse grid operator
> is defined
> >      after calling DMCoarsenHierarchy, but that failed.
> >
> >      I am solving Helmholtz with shifted Laplace, and managed to exploit
> DMDA to perform
> >      a multigrid solve on the preconditioner. In a next stage I want to
> implement the deflation
> >      using DMDA as well.
> >
> > 2) On http://www.mcs.anl.gov/petsc/documentation/referencing.html I see
> >
> > @Misc{petsc-web-page,
> >             author = {Satish Balay and Shrirang Abhyankar and Mark~F.
> Adams and Jed Brown and Peter Brune
> >                       and Kris Buschelman and Lisandro Dalcin and Victor
> Eijkhout and William~D. Gropp
> >                       and Dinesh Kaushik and Matthew~G. Knepley
> >                       and Lois Curfman McInnes and Karl Rupp and
> Barry~F. Smith
> >                       and Stefano Zampini and Hong Zhang and Hong Zhang},
> >             title =  {{PETS}c {W}eb page},
> >             url =    {http://www.mcs.anl.gov/petsc},
> >             howpublished = {\url{http://www.mcs.anl.gov/petsc}},
> >             year = {2016}
> >           }
> >
> >
> >
> > Is the last author mentioned twice intentionally?
> >
> > 3) On
> http://www.mcs.anl.gov/petsc/publications/petscapps-bib.html#OpenFOAM%202.2.1
> I see
> >
> > @misc{OpenFOAM
> > ,
> >
> >
> > title =       "OpenFOAM",
> >
> > howpublished  =       "\url{http://www.openfoam.com}",
> >
> > url   =       {http://www.openfoam.com},
> >
> > note  =       "OpenFOAM is a free, open source CFD software package. It
> allows PETSc linear algebra and solvers to be used underneath.",
> >
> > key   =       "OpenFOAM 2.2.1"
> >
> > }
> >
> >
> > Do you have more information on the use of PETSc within OpenFoam?
>
>   Very good question. It seems that this citation is wrong or no longer
> valid; I have removed it from the PETSc repository. I could find no mention
> of PETSc usage in the OpenFoam and its third party packages. I think we
> should not have been listing this citation.
>
>
> This suggests that people are using it with OpenFOAM:
> http://powerlab.fsb.hr/ped/kturbo/OpenFOAM/slides/PatersonNuTTS2009.pdf
>
> In fact, they use PETSc in the dynamic overset grid implementation for
> OpenFOAM, which I think is an approved extension:
>
>
> http://web.student.chalmers.se/groups/ofw5/Abstracts/DavidBogerAbstractOFW5.pdf
>
>      Matt
>
>
>
>    Barry
>
> >
> > 4) @matt in response to a question he raised in Vienna
> >
> > MIPSE is a BEM solver. Details are on:
> >
> http://www.g2elab.grenoble-inp.fr/plateforms/mipse-modeling-of-interconnected-power-systems-632862.kjsp?RH=G2ELAB_R-MAGE
> >
> > Cheers, Domenico Lahaye.
>
> >
>
>
>
>
> --
> 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
>
>
>


-- 
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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