Element-wise sum of data from all processes with result left only on one.
MPI mapping mpi_reduce
Type | Intent | Optional | Attributes | Name | ||
---|---|---|---|---|---|---|
integer(kind=int_8), | intent(inout), | CONTIGUOUS | :: | msg(:) |
Vector to sum (input) and (only on process root) result (output) |
|
integer, | intent(in) | :: | root | |||
type(mp_comm_type), | intent(in) | :: | gid |
Message passing environment identifier |
SUBROUTINE mp_sum_root_lv(msg, root, gid)
!! Element-wise sum of data from all processes with result left only on
!! one.
!!
!! MPI mapping
!! mpi_reduce
INTEGER(KIND=int_8), CONTIGUOUS, INTENT(INOUT) :: msg(:)
!! Vector to sum (input) and (only on process root) result (output)
INTEGER, INTENT(IN) :: root
TYPE(mp_comm_type), INTENT(IN) :: gid
!! Message passing environment identifier
CHARACTER(LEN=*), PARAMETER :: routineN = 'mp_sum_root_lv'
INTEGER :: handle, ierr, msglen
#if defined(__parallel)
INTEGER :: m1, taskid
INTEGER(KIND=int_8), ALLOCATABLE :: res(:)
#endif
ierr = 0
CALL timeset(routineN, handle)
msglen = SIZE(msg)
#if defined(__parallel)
CALL mpi_comm_rank(gid%handle, taskid, ierr)
IF (ierr /= 0) CALL mp_stop(ierr, "mpi_comm_rank @ "//routineN)
IF (msglen > 0) THEN
m1 = SIZE(msg, 1)
ALLOCATE (res(m1))
CALL mpi_reduce(msg, res, msglen, MPI_INTEGER8, MPI_SUM, &
root, gid%handle, ierr)
IF (ierr /= 0) CALL mp_stop(ierr, "mpi_reduce @ "//routineN)
IF (taskid == root) THEN
msg = res
END IF
DEALLOCATE (res)
END IF
CALL add_perf(perf_id=3, msg_size=msglen*int_8_size)
#else
MARK_USED(root)
MARK_USED(gid)
#endif
CALL timestop(handle)
END SUBROUTINE mp_sum_root_lv