[petsc-users] How to reorder the local part of the parallel mat?

[Jed Brown]

1. Partition the mesh
2. Create a sequential matrix representing local mesh adjacency
3. Use MATORDERINGRCM to get a new ordering for that sequential matrix
4. Broadcast the new global indices to neighbors


On Wed, Jan 16, 2013 at 2:26 PM, Fande Kong <fd.kong at siat.ac.cn> wrote:

> Barry, Thank you very much.
>
> What I want to do is to order the original mesh.  I have partitioned the
> mesh. But I want to reorder the vertices. Thus I create a matrix that
> represent the relationships of the vertices, and then I want to use the
> ordering methods in petsc to reorder the vertices by using matgetordering.
>
> What should I do if I want to use the ordering methods
> (e.g. MATORDERINGRCM ) in petsc to reorder the mesh vertices?
>
> On Wed, Jan 16, 2013 at 1:10 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
>>
>> On Jan 16, 2013, at 1:53 PM, Fande Kong <fd.kong at siat.ac.cn> wrote:
>>
>> > Hi all,
>> >
>> > I create a parallel mat with type MATMPIAIJ, and use the MatGetOrdering
>> to reorder it. But it doesn't work. Who can tell me how to do that? I just
>> want to reorder the local part of the matrix.
>>
>>    We don't have code in place for this type of thing. Maybe if you
>> explain why you would like it we could suggest alternatives.
>>
>>     Generally we recommend ordering the original mesh appropriately so
>> that the resulting matrices have good orderings and don't recommend
>> reordering the matrices directly (except for direct solvers).
>>
>>    Barry
>>
>> >
>> > Thanks,
>> >
>> > --
>> > Fande Kong
>> > ShenZhen Institutes of Advanced Technology
>> > Chinese Academy of Sciences
>>
>>
>>
>
>
> --
> Fande Kong
> ShenZhen Institutes of Advanced Technology
> Chinese Academy of Sciences
>
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