MPI.Op and performing operation

Question

I'd like to use MPI.Op class to perform some operation represented by instance of it (in this case MPI.SUM).

Here is my snippet:

input = numpy.array(3, dtype='i')
output = numpy.array(3, dtype='i')
MPI.SUM.Reduce_local(input, output)

But when I try to run it I get this traceback:

Traceback (most recent call last):
  File "./mpi.py", line 37, in <module>
    MPI.SUM.Reduce_local(input, output)
  File "Op.pyx", line 75, in mpi4py.MPI.Op.Reduce_local (src/mpi4py.MPI.c:54825)
AttributeError: 'mpi4py.MPI.Op' object has no attribute 'scount'

I'm new to python so it's pretty possible that I'm making some kind of easy mistake. Any thoughts?

I'm using Python 2.6.6.

Answer 1

Okay, I have an answer to this question.

It seems that it was a bug in mpi4py library which is now fixed: https://bitbucket.org/mpi4py/mpi4py/commits/43c7388ad740e90cc7074c1c21857c3fd3880190

But if you don't have newest version of mpi4py you can still do this:

buffers = [[1,1],[2,2]]
result = reduce(MPI.SUM, buffers)

And a result will be: [3,3]