On Tue, Dec 21, 2010 at 5:49 AM, Thomas Witkowski < thomas.witkowski at tu-dresden.de> wrote:
> 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? > ParMetis has a balance constraint if you weight vertices. This will enforce equal size partitions. > 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. > ParMetis minimizes the overall boundary size, so I do not understand how you could see this slowdown. Matt > 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 > -- 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20101221/205fc2ce/attachment.htm>
