refined mpi handshake in preparation for adding mpi join for ssc#2408

Merged

JasonRuonanWang merged 3 commits intoornladios:masterfrom JasonRuonanWang:ssc-mpi-join

Aug 4, 2020

+50-30

Commits on Aug 4, 2020

refined mpi handshake in preparation for adding mpi join for ssc
JasonRuonanWang
committed
fixing windows warnings
JasonRuonanWang
committed
disable windows for mpi handshake because MPI_Comm_create_group does not work on windows
JasonRuonanWang
committed