[petsc-users] any reasons to distinguish MPIU_SUM from MPI_SUM?

[Satish Balay]

I think some MPI impls didn't provide some of the ops on MPI_COMPLEX
datatype.

So petsc provides these ops for PetscReal i.e MPIU_SUM, MPIU_MAX, MPIU_MIN

Satish

On Mon, 17 Aug 2015, Fande Kong wrote:

> Hi all,
> 
> I was wondering why, in Petsc,  MPI_Reduce with PetscInt needs MPI_SUM
> meanwhile MPI_Reduce with PetscReal needs MPIU_SUM? Do we have any special
> reasons to distinguish them?
> 
> Thanks,
> 
> Fande Kong,
>