Define rank mapping of MPI Interoperability #47
Description
Currently, the standard is very slim regarding MPI interoperability.
I propose to add a definition, that a GASPI rank is equal to the MPI rank in MPI_COMM_WORLD.
In addition we could think about an additional gaspi_proc_init, which takes an MPI communicator and only initializes GASPI for the group of that MPI communicator (also taking over the ranks of that communicator).