The call of MPI_Allgather with sendbuf and sendtype parameters equal to MPI_IN_PLACE and NULL correspondingly, produces the segmentation fault.
The problem is that sendtype is used even when sendbuf value is MPI_IN_PLACE. But according to the standard, sendtype and sendcount parameters should be ignored in this case.
Signed-off-by: Mikhail Kurnosov <mkurnosov@gmail.com>