[petsc-dev] PetscLayoutFindOwner and PetscLayoutFindOwnerIndex

[Jed Brown]

Pierre Jolivet via petsc-dev <petsc-dev at mcs.anl.gov> writes:

>> On 16 Oct 2019, at 8:01 PM, Zhang, Junchao <jczhang at mcs.anl.gov> wrote:
>> 
>> The value of "owner" should fit in PetscMPIInt.
>
> Are you implying that BuildSystem always promotes PetscInt to be able to store a PetscMPIInt (what if you configure with 32 bit indices and a 64 bit MPI implementation)?

This isn't possible at present.  MPI uses "int" and PETSc uses either
"int" or "int64_t".  On ILP64, they're all 64-bit, but there is
currently no way to use int32_t on ILP64 and there would need to be a
new MPI standard to make it use int64_t on LP64.