partitioning

[Yixun Liu]

Barry Smith wrote:
>
> PETSc currently only provides an interface using graphs. Note
> that since PETSc is just a library there is nothing stopping someone
> from calingl ParMetis or any other library anyway they want in the same
> code that uses PETSc.
>
> Barry
>
> On Feb 21, 2009, at 9:30 AM, Yixun Liu wrote:
>
>> Barry Smith wrote:
>>>
>>> On Feb 21, 2009, at 8:40 AM, Yixun Liu wrote:
>>>
>>>> Hi,
>>>> ex2 give an example on how to partition using ParMETIS by inputing
>>>> element graph and mesh. ParMETIS also provides function for
>>>> partitioning
>>>> without inputing graph. Does PETSc provide some interface for this?
>>>
>>> I doubt it. How can one partition a graph without providing the graph?
>>>
>>> Barry
>>>
>>>>
>>>>
>>>> Thanks.
>>>>
>>>> Yixun
>>>
>> Mesh can produce graph by taking into account the fact two neighboring
>> elements share same edge or surface, so we can let ParMETIS do it just
>> providing mesh as input. ParMETIS provides a function named as
>> ParMETIS_V3_PartMeshKway, which only takes a mesh as input. Internally,
>> this function use a mesh-to-graph routine(section 3.2 ParMETIS manual).
>
Thanks.
Another question is once I have partitioned the mesh into two parts and
each part uses local numbering. Now I need to assemble the matrix. Can I
do like this,
For local indices generate a 2x2 matrix (triangle) and then map each
local row into global row? Is it a better way?