[petsc-users] Regarding ksp ex42 - Citations

[domenico lahaye]

Dear Matthew, 
  I would like to place the FormJacobian statement in ex25.c in such a way that I can view the result on the different levels. Can you please point me to an example? 
  I would like to do above with Galerkin coarsening as well. So yes, I do expect that I will need the hooks attached to the different MG levels. I appreciate more pointers here as well. 
   Thanks, Domenico.  

From: Matthew Knepley <knepley at gmail.com>


 To: domenico lahaye <domenico_lahaye at yahoo.com> 
Cc: PETSc Users List <petsc-users at mcs.anl.gov>
 Sent: Monday, July 18, 2016 8:16 AM
 Subject: Re: [petsc-users] Regarding ksp ex42 - Citations
   
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 toattach 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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