[petsc-users] ERROR: MatPartitioningApply_Parmetis() ... Does not support any processor with 0 entries

[Barry Smith]

   Since you are starting with everything on one process just run the partitioner on one process 

    Barry

On Oct 22, 2011, at 4:14 AM, Dominik Szczerba wrote:

> Oh, you meant pmetis.c from src/mat/partition/impls/pmetis, not the
> same file in externalpackages/ParMetis-3.2.0-p1...
> 
> I removed this check:
> 
> #if 1
>  if ((vtxdist[rank+1] - vtxdist[rank]) < 1) {
>    SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Does not support any
> processor with %d entries",vtxdist[rank+1] - vtxdist[rank]);
>  }
> #endif
> 
> but it generates more errors in other files:
> 
> dsz at tharsis:~/pack/petsc-3.2-p3$ rgrep "Poor vertex distribution" *
> externalpackages/ParMetis-3.2.0-p1/ParMETISLib/ametis.c:
> printf("Error: Poor vertex distribution (processor with no
> vertices).\n");
> externalpackages/ParMetis-3.2.0-p1/ParMETISLib/ometis.c:
> printf("Error: Poor vertex distribution (processor with no
> vertices).\n");
> externalpackages/ParMetis-3.2.0-p1/ParMETISLib/rmetis.c:
> printf("Error: Poor vertex distribution (processor with no
> vertices).\n");
> externalpackages/ParMetis-3.2.0-p1/ParMETISLib/kmetis.c:
> printf("Error: Poor vertex distribution (processor with no
> vertices).\n");
> 
> I am not sure if tweaking parmetis code is a way I want to go...
> 
> How about different solutions:
> 
> 1) partitioning with metis and not parmetis? How to perform
> partitioning by definition just serially? I just have a mesh on master
> and want to get partitioning on master, I will take over then.
> 2) partitioning other than parmetis, will they work in my scenario? I
> see e.g. chaco in the docu, but can not specify it with
> -mat_partitioning_type chaco, I get an error. Are there any examples
> how to partition using different methods?
> 
> I just need a quick fix for this problem, not necessarily the best one
> for the moment...
> 
> Many thanks for any insight,
> Dominik
> 
> On Fri, Oct 21, 2011 at 11:58 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
>> On Fri, Oct 21, 2011 at 16:53, Dominik Szczerba <dominik at itis.ethz.ch>
>> wrote:
>>> 
>>> I can not find anything resembling any guards in pmetis.c as pet Petsc
>>> 3.2. Could you please refer me to the specific section?
>> 
>> $ grep -n 'Does not support any processor with' petsc-3.2/src/**/*.c
>> petsc-3.2/src/mat/partition/impls/pmetis/pmetis.c:61:
>>  SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_LIB,"Does not support any processor with
>> %d entries",vtxdist[rank+1] - vtxdist[rank]);