[petsc-dev] question about PETSc.Vec.sum()

[Barry Smith]

On Jun 21, 2011, at 10:59 AM, Jed Brown wrote:

> On Tue, Jun 21, 2011 at 18:56, Aron Ahmadia <aron.ahmadia at kaust.edu.sa> wrote:
> PETSc could also just provide a VecReduce and VecReduceStride operation, which might simplify the programming effort a bit.
> 
> That would be neat, especially if it used MPI_Op for the reduction. You would need MPI-2.2 to have MPI_Reduce_local() for user-defined operations, but it would be more flexible and less code than the current approach.

  Eventually when we switch to Vec being an abstract vector collection object (we don't know that this means yet) all of this stuff becomes trivial and natural and doesn't need a whole bunch of new APIs

   Barry