- requests[i - 1] = Request::irecv(nullptr, 0, MPI_BYTE, MPI_ANY_SOURCE, COLL_TAG_BARRIER, comm);
- requests[i] = Request::isend(nullptr, 0, MPI_BYTE, (i + 1) / 2, COLL_TAG_BARRIER, comm);
+ requests[i - 1] = Request::irecv(nullptr, 0, MPI_BYTE, MPI_ANY_SOURCE, system_tag, comm);
+ requests[i] = Request::isend(nullptr, 0, MPI_BYTE, (i + 1) / 2, system_tag, comm);