Element-wise sum of a rank-2 array on all processes.
see mp_sum_c
Type | Intent | Optional | Attributes | Name | ||
---|---|---|---|---|---|---|
complex(kind=real_4), | intent(inout), | CONTIGUOUS | :: | msg(:,:) |
Matrix to sum and result |
|
integer, | intent(in) | :: | gid |
SUBROUTINE mp_sum_cm(msg, gid)
!! Element-wise sum of a rank-2 array on all processes.
!! @note see mp_sum_c
COMPLEX(kind=real_4), CONTIGUOUS, INTENT(INOUT) :: msg(:, :)
!! Matrix to sum and result
INTEGER, INTENT(IN) :: gid
CHARACTER(LEN=*), PARAMETER :: routineN = 'mp_sum_cm'
INTEGER :: handle, ierr
#if defined(__parallel)
INTEGER, PARAMETER :: max_msg = 2**25
INTEGER :: m1, msglen, step, msglensum
#endif
ierr = 0
CALL timeset(routineN, handle)
#if defined(__parallel)
! chunk up the call so that message sizes are limited, to avoid overflows in mpich triggered in large rpa calcs
step = MAX(1, SIZE(msg, 2)/MAX(1, SIZE(msg)/max_msg))
msglensum = 0
DO m1 = LBOUND(msg, 2), UBOUND(msg, 2), step
msglen = SIZE(msg, 1)*(MIN(UBOUND(msg, 2), m1 + step - 1) - m1 + 1)
msglensum = msglensum + msglen
IF (msglen > 0) THEN
CALL mpi_allreduce(MPI_IN_PLACE, msg(LBOUND(msg, 1), m1), msglen, MPI_COMPLEX, MPI_SUM, gid, ierr)
IF (ierr /= 0) CALL mp_stop(ierr, "mpi_allreduce @ "//routineN)
END IF
END DO
CALL add_perf(perf_id=3, msg_size=msglensum*(2*real_4_size))
#else
MARK_USED(msg)
MARK_USED(gid)
#endif
CALL timestop(handle)
END SUBROUTINE mp_sum_cm