Hi all, The Collectives WG would like to read issue 87 (PR 43), which is an errata that adds a clarification regarding the use of MPI_PROC_NULL as a valid rank value for graph and dist graph topologies. Issue: https://github.com/mpi-forum/mpi-issues/issues/87 PR: https://github.com/mpi-forum/mpi-standard/pull/43 PDF: https://github.com/mpi-forum/mpi-standard/files/2026783/mpi-report-ticket87.... Cheers, Dan. — Dr Daniel Holmes PhD Applications Consultant in HPC Research [email protected]<mailto:[email protected]> Phone: +44 (0) 131 651 3465 Mobile: +44 (0) 7940 524 088 Address: Room 3415, JCMB, The King’s Buildings, Edinburgh, EH9 3FD — The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. — The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.