mp_allgatherv_zv Subroutine

      SUBROUTINE mp_allgatherv_zv(msgout, msgin, rcount, rdispl, gid)
      !! Gathers vector data from all processes and all processes receive the
      !! same data
      !!
      !! Data size
      !! Processes can send different-sized data
      !!
      !! Ranks
      !! The last rank counts the processes
      !!
      !! Offsets
      !! Offsets are from 0
      !!
      !! MPI mapping
      !! mpi_allgather

         COMPLEX(kind=real_8), CONTIGUOUS, INTENT(IN)        :: msgout(:)
         !! Rank-1 data to send
         COMPLEX(kind=real_8), CONTIGUOUS, INTENT(OUT)       :: msgin(:)
         !! Received data
         INTEGER, CONTIGUOUS, INTENT(IN)          :: rcount(:), rdispl(:)
         INTEGER, INTENT(IN)                      :: gid
         !! Size of sent data for every process
         !! Offset of sent data for every process
         !! Message passing environment identifier

         CHARACTER(LEN=*), PARAMETER :: routineN = 'mp_allgatherv_zv'

         INTEGER                                  :: handle, ierr
#if defined(__parallel)
         INTEGER                                  :: scount
#endif

         ierr = 0
         CALL timeset(routineN, handle)

#if defined(__parallel)
         scount = SIZE(msgout)
         CALL MPI_ALLGATHERV(msgout, scount, MPI_DOUBLE_COMPLEX, msgin, rcount, &
                             rdispl, MPI_DOUBLE_COMPLEX, gid, ierr)
         IF (ierr /= 0) CALL mp_stop(ierr, "mpi_allgatherv @ "//routineN)
#else
         MARK_USED(rcount)
         MARK_USED(rdispl)
         MARK_USED(gid)
         msgin = msgout
#endif
         CALL timestop(handle)
      END SUBROUTINE mp_allgatherv_zv