[petsc-users] Edge-cut information for CHACO

[Fande Kong]

On Thu, Dec 5, 2019 at 12:34 PM Mark Adams <mfadams at lbl.gov> wrote:

>
>
> On Thu, Dec 5, 2019 at 11:20 AM Eda Oktay <eda.oktay at metu.edu.tr> wrote:
>
>> Hello all,
>>
>> I am trying to find edge cut information of ParMETIS and CHACO. When I
>> use ParMETIS,
>> MatPartitioningViewImbalance(part,partitioning)
>> works and it gives also number of cuts.
>>
>> However, when I used CHACO, it only gives imbalance information, not edge
>> cut. I have index sets but I couldn't find how to calculate edge cut.
>>
>
> I've never heard of edge-cuts wrt Chaco. I'm sure it does not collect that
> information but you could look at the code.
>

Not sure chaco supports this or not, but we do not collect edge cuts from
Chaco. If you want, it is actually very easy to collect all these data at
the PETSc side.


>
>
>>
>> Also, does ParMETIS calculate edge cuts according to the values of
>> weights or number of weights?
>>
>
> Good question, I would assume this is an integer, the number of edge cuts,
> and not the sum of the weights. If it prints and integer then that would be
> a hint.
>

The edge-cuts in ParMETIS take the edge weights into account.

For example, if you have an edge along which the domain is partitioned. If
the weight of that edge is 10, and the number of edge-cuts is 10 instead of
1.


Fande,


>
>>
>> Thanks!
>>
>> Eda
>>
>
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