Hi everyone, when I construct a communicator from a group, the resulting communicator is invalid. Here's an example. //------------------------------ example begin -------------------------------// #include <boost/mpi/communicator.hpp> #include <boost/mpi/environment.hpp> #include <boost/mpi/group.hpp> int main(int ac, char** av) { boost::mpi::environment env(ac, av); boost::mpi::communicator world; int rank[] = {0}; boost::mpi::communicator comm(world, world.group().include(rank, rank + 1)); } //------------------------------ example end ---------------------------------// This program throws an exception when comm is destroyed (MPI_Comm_free: MPI_ERR_COMM: invalid communicator). If I try calling comm.size() or something, it throws an "invalid communicator" exception then, too. However, asserting on comm succeeds, so clearly comm is confused about its state. I found some outstanding tickets (5596, 6436) but those discussions don't seem to go anywhere. Can anyone offer help?