[petsc-dev] ISLocalToGlobalMappingGetInfo

[Smith, Barry F.]

  The documents and the code indicate that nproc should be 1 in this case. So there is a bug, if you are unable to determine the cause I can try to look at it but have stones of things to do.

  Barry


> On Aug 9, 2019, at 12:37 AM, Pierre Jolivet <pierre.jolivet at enseeiht.fr> wrote:
> 
> Again, with only 2 processes, where nproc is set to 2, I get the following numprocs and indices arrays on rank 0:
> 0	110 111 112 113 114 115 116 117 … 
> 1	110 111 112 113 114 115 116 117 …
> Are these the expected values? If so, what is the true definition of nproc, please?
> 
> Thanks,
> Pierre
> 
>> On 9 Aug 2019, at 3:45 AM, Smith, Barry F. <bsmith at mcs.anl.gov> wrote:
>> 
>> 
>> There could be a bug. Perhaps check the entries for that "extra" connection, are they all actual meaningful connections. The code that fills up these data structures is somewhat involved.
>> 
>>  Barry
>> 
>> 
>>> On Aug 8, 2019, at 9:39 AM, Pierre Jolivet via petsc-dev <petsc-dev at mcs.anl.gov> wrote:
>>> 
>>> Hello,
>>> When I use ISLocalToGlobalMappingGetInfo, e.g., in src/ksp/ksp/examples/tutorials/ex71.c ISLocalToGlobalMappingGetInfo(map, &nproc, &procs, &numprocs, &indices), I get the following value for nproc:
>>> - with 1 process: 0
>>> - with 2 processes: 2
>>> In the source code, it says that nproc is the “number of processors that are connected to this one”.
>>> How come this value is equal to the size of the global communicator when using 2 processes?
>>> According to the comment in the source code, shouldn’t the returned value be 1?
>>> 
>>> Thanks,
>>> Pierre
>> 
>