Sums a datum from all processes with result left on all processes.
MPI mapping mpi_allreduce
Type | Intent | Optional | Attributes | Name | ||
---|---|---|---|---|---|---|
integer(kind=int_4), | intent(inout) | :: | msg |
Datum to sum (input) and result (output) |
||
type(mp_comm_type), | intent(in) | :: | gid |
Message passing environment identifier |
SUBROUTINE mp_sum_i (msg, gid)
!! Sums a datum from all processes with result left on all processes.
!!
!! MPI mapping
!! mpi_allreduce
INTEGER(KIND=int_4), INTENT(INOUT) :: msg
!! Datum to sum (input) and result (output)
TYPE(mp_comm_type), INTENT(IN) :: gid
!! Message passing environment identifier
CHARACTER(LEN=*), PARAMETER :: routineN = 'mp_sum_i'
INTEGER :: handle, ierr, msglen
ierr = 0
CALL timeset(routineN, handle)
msglen = 1
#if defined(__parallel)
CALL mpi_allreduce(MPI_IN_PLACE, msg, msglen, MPI_INTEGER, MPI_SUM, gid%handle, ierr)
IF (ierr /= 0) CALL mp_stop(ierr, "mpi_allreduce @ "//routineN)
CALL add_perf(perf_id=3, msg_size=msglen*int_4_size)
#else
MARK_USED(msg)
MARK_USED(gid)
#endif
CALL timestop(handle)
END SUBROUTINE mp_sum_i