CALL MPI_Comm_split_type(MPI_COMM_WORLD, MPI_COMM_TYPE_SHARED&
, 0, MPI_INFO_NULL, hostcomm,ierr)
    CALL MPI_Comm_rank(hostcomm, hostrank,ierr)

    allocate(arrayshape(4))
    arrayshape=(/ nroot1,nroot1,nroot1,nroot1 /)
    if (hostrank == 0) then
        windowsize = int(nroot1**4,MPI_ADDRESS_KIND)*&
8_MPI_ADDRESS_KIND ! *8 since there are 8 bytes in a double
    else
        windowsize = 0_MPI_ADDRESS_KIND
    end if
    disp_unit = 1

    CALL MPI_Win_allocate_shared(windowsize, disp_unit, &
MPI_INFO_NULL, hostcomm, baseptr, win,ierr)
    CALL MPI_Win_allocate_shared(windowsize, disp_unit, &
MPI_INFO_NULL, hostcomm, baseptr2, win2,ierr)

    ! Obtain the location of the memory segment
    if (hostrank /= 0) then
        CALL MPI_Win_shared_query(win, 0, windowsize, disp_unit,&
 baseptr,ierr)
        CALL MPI_Win_shared_query(win2, 0, windowsize, disp_unit,&
 baseptr2,ierr)
    end if

    ! baseptr can now be associated with a Fortran pointer
    ! and thus used to access the shared data
    CALL C_F_POINTER(baseptr, matrix_elementsy,arrayshape)
    CALL C_F_POINTER(baseptr2, matrix_elementsz,arrayshape)