使用MPI（Fortran）时出现Seg故障

我对MPI和Fortran都很陌生。几个小时来，我一直在努力想办法解决这个问题，但运气不好。在我下面的代码中，一切都很正常（除了我的

s

变量在进程之间是隔离的这一事实。当我尝试实现

MPI\u SEND

和

MPI\u RECV

时，我经常遇到seg故障。我似乎不知道问题是什么

  SUBROUTINE do_mpi_simpsons(l, u, n)
    INTEGER, INTENT (in) :: l, u, n
    ! REAL, INTENT (in) :: func
    DOUBLE PRECISION  :: result, walltime
    INTEGER :: clock_start, clock_rate, clock_max, clock_end
    DOUBLE PRECISION :: h, s, argVal, finalS
    INTEGER :: rank, size, ierror, tag, status(MPI_STATUS_SIZE), count, start, stop

    walltime = 0.0D0

    h = (u - l) / dble(n)
    s = func_hw(dble(l)) + func_hw(dble(u))

    CALL system_clock(clock_start, clock_rate, clock_max)
    CALL MPI_INIT(ierror)
    CALL MPI_COMM_SIZE(MPI_COMM_WORLD, size, ierror)
    CALL MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierror)

    count = n / size

    start = rank * count
    stop = start + count -1

    ! WRITE(*,*) "Start: ", start
    ! WRITE(*,*) "Stop: ", stop
    WRITE(*,*) rank

    DO i = start, stop, 2
      s = s + 4 * func_hw(dble(l)+dble(i)*h)
    END DO
    DO i = start+1, stop-1, 2
      s = s + 2 * func_hw(dble(l)+dble(i)*h)
    END DO

    ! This block is causing the seg faults
    IF(rank.eq.0) THEN
        finalS = s
        DO i = 1, size - 1
          CALL MPI_RECV(s, 64, MPI_DOUBLE, i, 1, MPI_COMM_WORLD, status, ierror)
          finalS = finalS + s
        END DO
    ELSE
        CALL MPI_SEND(s, 64, MPI_DOUBLE, 0, 1, MPI_COMM_WORLD, ierror)    
    END IF

    CALL MPI_FINALIZE(ierror)
    CALL system_clock(clock_end, clock_rate, clock_max)

    walltime = walltime + real(clock_end - clock_start) / real(clock_rate)
    result = s * h / 3 

    WRITE(*,*) "walltime = ", walltime, " seconds"
    WRITE(*,*) "result = ", result
  END SUBROUTINE

---

s

似乎是一个标量变量，但您将其作为64个双精度数组传递给MPI例程。这就是我没有正确理解参数的原因。这似乎解决了问题。因此，您可能需要查看

MPI\u REDUCE

。它的作用与单个MPI调用中的代码块相同，而且肯定更有效这样做很有效率。