Guillaume, MPI_Comm is an opaque handler that should not be interpreted by an end user.
Open MPI chose to implement is as an opaque pointer, and MPICH chose to implement it as a 32 bits unsigned integer. The 44000000 value strongly suggests you are using MPICH and you are hence posting to the wrong mailing list Cheers, Gilles On Fri, Jun 24, 2022 at 9:06 PM Guillaume De Nayer via users < users@lists.open-mpi.org> wrote: > Hi Gilles, > > MPI_COMM_WORLD is positive (44000000). > > In a short code I wrote I have something like that: > > MPI_Comm_dup(MPI_COMM_WORLD, &world); > cout << "intra-communicator: " << "world" << "---" << hex << world << endl; > > It returns "84000006" (in hex). > > later I have: > > MPI_Comm_accept(port_name, MPI_INFO_NULL, 0, world, &interClient); > cout << "intercommunicator interClient=" << interClient << endl; > > After connection from a third party client it returns "c4000003" (in hex). > > Both 84000006 and c4000003 are negative integer in dec. > > I don't know if it is "normal". Therefore I'm looking about rules on the > communicators, intercommunicators. > > Regards, > Guillaume > > > On 06/24/2022 11:56 AM, Gilles Gouaillardet via users wrote: > > Guillaume, > > > > what do you mean by (the intercommunicators are all negative"? > > > > > > Cheers, > > > > Gilles > > > > On Fri, Jun 24, 2022 at 4:23 PM Guillaume De Nayer via users > > <users@lists.open-mpi.org <mailto:users@lists.open-mpi.org>> wrote: > > > > Hi, > > > > I am new on this list. Let me introduce myself shortly: I am a > > researcher in fluid mechanics. In this context I am using softwares > > related on MPI. > > > > I am facing a problem: > > - 3 programs forms a computational framework. Soft1 is a coupling > > program, i.e., it opens an MPI port at the beginning. Soft2 and Soft3 > > are clients, which connect to the coupling program using > > MPI_Comm_connect. > > - After the start and the connections of Soft2 and Soft3 with Soft1, > it > > hangs. > > > > I started to debug this issue and as usual I found another issue (or > > perhaps it is not an issue): > > - The intercommunicators I get between Soft1-Soft2 and Soft1-Soft3 > are > > all negative (running on CentOS 7 with infiniband Mellanox OFED > driver). > > - Is there some standard about communicator? I don't find anything > > about > > this topic. > > - What is a valid communicator, intercommunicator? > > > > thx a lot > > Regards > > Guillaume > > > > >
