Hardware-based communicator split accepted in MPI 4.0

G. Mercier’s proposal for hardware-topology-based MPI communicator split passed the 2nd vote at the MPI Forum meeting on June 30th, which means it will be in the revision 4.0 of the MPI standard (official release in 2020Q4).
The “Guided” mode is described here while the “Unguided” mode is here. A prototype implementation is already available here.