[petsc-users] ParMETIS question

[Thomas Witkowski]

Hi,

I have a not directly PETSc related question, but I hope to get some 
answer from the community here. In my FEM code, I make use of ParMETIS 
to partition the mesh. I make direct use of this library and not of 
PETSc's ParMETIS integration. The initial partition is always fine, but 
I use the ParMETIS_V3_AdaptiveRepart function for repartition the mesh 
due to local mesh adaption. In most cases, the result is fine, but there 
are two points, where I have trouble with:

1) Sometimes ParMETIS generates empty partitions, i.e., a processor has 
zero mesh elements. This is something my code cannot handle. Is this a 
bug or a feature? If it is a feature, is there any possiblity to disable it?

2) In most cases the specific partitions are not connected. If I put all 
data to ParMETIS in a correct way, is this okay? My code can handle it, 
but is slows down the computation due to larger interior boundaries and 
therefore to more communications.

Does anyone of you know an answer to these question? Is there a debug 
mode in ParMETIS, where I can see which data is set to its function calls?

Regards,

Thomas