[petsc-users] How rto use multigrid?

[Matthew Knepley]

On Tue, Oct 30, 2012 at 7:41 AM, TAY wee-beng <zonexo at gmail.com> wrote:

>  On 28/10/2012 2:17 PM, Jed Brown wrote:
>
> Algebraic multigrid can be used directly, -pc_type gamg
> -pc_gamg_agg_nsmooths 1. Geometric either required that you use the PCMG
> interface to set interpolation (and provide a coarse operator for
> non-Galerkin) or use a DM that provides coarsening capability.
>
> What kind of problem are you solving?
>
>
> Hi,
>
> May I know if there is an example which explains using the geometric MG,
> either using PCMG or DM?
>

SNES ex5 and ex19 both use MG.

   Matt


> Yours sincerely,
>
> TAY wee-beng
>
>
>  On Oct 28, 2012 6:09 AM, "w_ang_temp" <w_ang_temp at 163.com> wrote:
>
>>  Hello,
>>    I want to use the multigrid as a preconditioner. The introduction
>> about it in the manual is little.
>> So are there some typical examples or details about multigrid? Is it used
>> just like other preconditioners
>> like jacobi, sor, which can be simply used in the cammand line options?
>>    Thanks.
>>                                                                        Jim
>>
>>
>>
>


-- 
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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