What: Add neighborhood collective support to the trunk. These operations are required for MPI-3 compliance.
When: One week: 9/19. This code is targeted for 1.7.4 and should have plenty of time to cook in the trunk.
The attached patch implements the neighborhood collectives defined in MPI-3. Please pay special attention to the man pages (the wording on buffer ordering is directly copy and pasted from MPI-3), fortran bindings, and MPI standards compliance. I have implemented simple tests for cartesian, graph, and dist graph topologies for the Open MPI/IBM test suite and all tests pass. I will push those tests to MTT tomorrow.