[petsc-users] Solving problem using multigrid

[Matthew Knepley]

On Mon, Nov 19, 2018 at 1:48 PM Fazlul Huq via petsc-users <
petsc-users at mcs.anl.gov> wrote:

> Thanks.
> So, is it like if I run the same code using -pc_type gamg then it will use
> algebraic multigrid to solve the problem?
>

Yes.


> I have hypre configured with --download-hypre.
>

Then you can use -pc_type hypre -pc_hypre_type boomeramg


> Agin, if I want to use geometric multigrid, should I go with domain
> management (DM)?
>

Yes, or you can manage all the grids yourself and talk to PCMG directly.


> Now I am planning to go through examples with DM. Will it be a right
> approach to start?
>

Possibly. Note that GMG is much more involved than AMG.

  Thanks,

     Matt


> Thanks again.
> Sincerely,
> Huq
>
> On Sun, Nov 18, 2018 at 4:23 PM Mark Adams <mfadams at lbl.gov> wrote:
>
>> The manual is pretty clear on this, but your code is purely algebraic,
>> that is you do not use a DM, and so you will need to use algebraic
>> multigrid (AMG). So you want to look at AMG preconditioners (-pc_type gamg
>> [or hypre if you configured with --download-hypre]).
>>
>> Mark
>>
>> On Sun, Nov 18, 2018 at 1:28 PM Fazlul Huq via petsc-users <
>> petsc-users at mcs.anl.gov> wrote:
>>
>>> Hello PETSc developers,
>>>
>>> I have solved a problem using ksp. Please find the problem in attachment
>>> 1 and PETSc code for solution in attachment 2.
>>> Now I need to solve the same problem using multigrid.
>>> I never solved problem using multigrid. Can you please guide me about
>>> steps that I should follow
>>> to solve this problem using multigrid.
>>>
>>> Thanks.
>>> Sincerely,
>>> Huq
>>> --
>>>
>>> Fazlul Huq
>>> Graduate Research Assistant
>>> Department of Nuclear, Plasma & Radiological Engineering (NPRE)
>>> University of Illinois at Urbana-Champaign (UIUC)
>>> E-mail: huq2090 at gmail.com
>>>
>>
>
> --
>
> Fazlul Huq
> Graduate Research Assistant
> Department of Nuclear, Plasma & Radiological Engineering (NPRE)
> University of Illinois at Urbana-Champaign (UIUC)
> E-mail: huq2090 at gmail.com
>


-- 
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

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20181119/c54c1608/attachment.html>