mp_max_zv Subroutine

      SUBROUTINE mp_max_zv(msg, gid)
      !! Finds the element-wise maximum of a vector with the result left on
      !! all processes.
      !! @note see mp_max_z

         COMPLEX(kind=real_8), CONTIGUOUS, INTENT(INOUT)     :: msg(:)
         !! Find maximum among these data (input) and maximum (output)
         INTEGER, INTENT(IN)                      :: gid

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

         INTEGER                                  :: handle, ierr, msglen

         ierr = 0
         CALL timeset(routineN, handle)

         msglen = SIZE(msg)
#if defined(__parallel)
         CALL mpi_allreduce(MPI_IN_PLACE, msg, msglen, MPI_DOUBLE_COMPLEX, MPI_MAX, gid, ierr)
         IF (ierr /= 0) CALL mp_stop(ierr, "mpi_allreduce @ "//routineN)
         CALL add_perf(perf_id=3, msg_size=msglen*(2*real_8_size))
#else
         MARK_USED(gid)
#endif
         CALL timestop(handle)
      END SUBROUTINE mp_max_zv