fortran - 将 coarray 子数组传递给函数会给出数组的错误部分

Question

我试图了解如何将多维联合数组的切片传递给函数。我想使用这样的函数:

    function get_int_vec(vec_int_2get, rank) result(ret_val)
      implicit none
      integer,  dimension(:), codimension[*], intent(in) :: vec_int_2get
      integer, intent(in) :: rank
      integer, allocatable, dimension(:) :: ret_val 

      ret_val = vec_int_2get(:)[rank]

    end function ! get_int_vec

它可以很好地获取整个数组。 但是当传递 coarray 的切片时，例如:

    vec_getA(:) = get_int_vec(matrix_A(n, :), rank)

其中 matrix_A 声明为

    integer, dimension(:, :), codimension[:],  allocatable :: matrix_A

并且正确分配，我总是得到matrix_A的第一列而不是第n列。

gfortran passing conventions说:

"with -fcoarray=lib [...] 属于不可分配 coarrays 虚拟参数的标记和偏移量作为隐藏参数沿着字符长度隐藏参数传递。标记是一个不透明指针标识 coarray 和偏移量是类型为 C_PTRDIFF_T 的按值传递整数，表示 coarray 的基地址与传递的标量或传递的数组的第一个元素之间的字节偏移量。

所以我希望该函数也能与矩阵切片一起正常工作，因为距矩阵开头的偏移量应该传递给函数。

我做错了什么吗？

如果您感兴趣:我正在使用 Intel Parallel Studio XE 2018 集群版本进行编译，而不是 coarrays 的 OpenCoarrays 版本。

Answer 1

这似乎是 Intel ifort 2018 中的一个错误。您的代码语法似乎符合 Fortran 2008 标准 ( here )。使用 OpenCoarrays 和 GFortran 编译的相同代码会产生预期结果。这是您的问题的(不是那么简单但)有效的实现:

module coarrayFunc
    implicit none
contains
    function get_int_vec(vec_int_2get, rank) result(ret_val)
        implicit none
        integer,  dimension(:), codimension[*], intent(in) :: vec_int_2get
        integer, intent(in) :: rank
        integer :: ret_val(3)
        !integer :: ret_val(size(vec_int_2get)) ! using this results in internal compiler error when compiled with ifort.
        !integer, allocatable :: ret_val(:) ! both ifort and OpenCoarrays (GFortran) compile with this declaration, however both ifort give wrong results.
        ret_val = vec_int_2get(:)[rank]
    end function ! get_int_vec
end module coarrayFunc

program testNoncontiguousCoarray
    use coarrayFunc
    implicit none
    integer, allocatable    :: matrix_A(:,:)[:], dummy(:)
    integer                 :: rank, n, i, j, image
    integer, parameter      :: ilower = 1, iupper = 5
    integer, parameter      :: jlower = 1, jupper = 3

    allocate( matrix_A(ilower:iupper,jlower:jupper)[*] )

    do i = ilower, iupper
        do j = jlower, jupper
            matrix_A(i,j) = this_image()*100 + i*10 + j
        end do
    end do

    ! print matrix_A on each image
    sync all
    if (this_image()==1) then
        do image = 1, num_images()
            write(*,"(*(g0))") "matrix_A on image ", image, ":"
            do i = ilower, iupper
                write(*,"(*(g8.1))") matrix_A(i,:)[image]
            end do
            write(*,"(*(g0))")
        end do
        sync images(*)
    else
        sync images(1)
    end if
    sync all

    n = iupper
    rank = this_image()
    !rank = num_images()

    sync all
    if (this_image()==1) then
        write(*,"(*(g0))")
        write(*,"(*(g0))") "On all images: "
        write(*,"(*(g0))") "n = ", n
        write(*,"(*(g0))")
    end if
    sync all

    if (this_image()==1) then
        write(*,"(*(g0,' '))") "On Image ", this_image(), ": matrix_A( n =", n, ", : )[",rank,"] = ", matrix_A(n,:)[rank]
        dummy = get_int_vec(matrix_A(n,:), rank)
        write(*,"(*(g0,' '))") "On Image ", this_image(), ": get_int_vec( matrix_A( n =", n, ", : ), rank =", rank, ") = " &
                               , dummy
    else
        sync images (this_image()-1)
        write(*,"(*(g0,' '))") "On Image ", this_image(), ": matrix_A( n =", n, ", : )[",rank,"] = ", matrix_A(n,:)[rank]
        dummy = get_int_vec(matrix_A(n,:), rank)
        write(*,"(*(g0,' '))") "On Image ", this_image(), ": get_int_vec( matrix_A( n =", n, ", : ), rank =", rank, ") = " &
                               , dummy
    end if
    call sleep(1)
    if (this_image()<num_images()) sync images (this_image()+1)

end program testNoncontiguousCoarray

使用 OpenCoarrays 编译并运行此代码会产生:

matrix_A on image 1:
    111     112     113
    121     122     123
    131     132     133
    141     142     143
    151     152     153

matrix_A on image 2:
    211     212     213
    221     222     223
    231     232     233
    241     242     243
    251     252     253

matrix_A on image 3:
    311     312     313
    321     322     323
    331     332     333
    341     342     343
    351     352     353

matrix_A on image 4:
    411     412     413
    421     422     423
    431     432     433
    441     442     443
    451     452     453


On all images: 
n = 5

On Image  1 : matrix_A( n = 5 , : )[ 1 ] =  151 152 153 
On Image  1 : get_int_vec( matrix_A( n = 5 , : ), rank = 1 ) =  151 152 153 
On Image  2 : matrix_A( n = 5 , : )[ 2 ] =  251 252 253 
On Image  2 : get_int_vec( matrix_A( n = 5 , : ), rank = 2 ) =  251 252 253 
On Image  3 : matrix_A( n = 5 , : )[ 3 ] =  351 352 353 
On Image  3 : get_int_vec( matrix_A( n = 5 , : ), rank = 3 ) =  351 352 353 
On Image  4 : matrix_A( n = 5 , : )[ 4 ] =  451 452 453 
On Image  4 : get_int_vec( matrix_A( n = 5 , : ), rank = 4 ) =  451 452 453

输出人们期望得到的结果。请注意，我已经调整了您的原始函数，以便该函数的结果将是一个自动数组而不是可分配的(这似乎是 OpenCoarrays 中的另一个错误，即可分配的输出返回错误的结果)。使用 ifort 2018 Windows 运行相同的代码将重现您在自己的实现中观察到的错误:

>set FOR_COARRAY_NUM_IMAGES=4

>ifort /Qcoarray=shared testNoncontiguousCoarray.f90 -o run.exe
Intel(R) Visual Fortran Intel(R) 64 Compiler for applications running on Intel(R) 64, Version 18.0.2.185 Build 20180210
Copyright (C) 1985-2018 Intel Corporation.  All rights reserved.

Microsoft (R) Incremental Linker Version 14.13.26129.0
Copyright (C) Microsoft Corporation.  All rights reserved.

-out:run.exe
-subsystem:console
testNoncontiguousCoarray.obj

>run.exe
matrix_A on image 1:
     111     112     113
     121     122     123
     131     132     133
     141     142     143
     151     152     153

matrix_A on image 2:
     211     212     213
     221     222     223
     231     232     233
     241     242     243
     251     252     253

matrix_A on image 3:
     311     312     313
     321     322     323
     331     332     333
     341     342     343
     351     352     353

matrix_A on image 4:
     411     412     413
     421     422     423
     431     432     433
     441     442     443
     451     452     453


On all images:
n = 5

On Image  1 : matrix_A( n = 5 , : )[ 1 ] =  151 152 153
On Image  1 : get_int_vec( matrix_A( n = 5 , : ), rank = 1 ) =  111 112 113
On Image  2 : matrix_A( n = 5 , : )[ 2 ] =  251 252 253
On Image  2 : get_int_vec( matrix_A( n = 5 , : ), rank = 2 ) =  211 212 213
On Image  3 : matrix_A( n = 5 , : )[ 3 ] =  351 352 353
On Image  3 : get_int_vec( matrix_A( n = 5 , : ), rank = 3 ) =  311 312 313
On Image  4 : matrix_A( n = 5 , : )[ 4 ] =  451 452 453
On Image  4 : get_int_vec( matrix_A( n = 5 , : ), rank = 4 ) =  411 412 413

正如您问题的评论中所提到的，请考虑编写一个最小的工作代码示例来重现您收到的错误，并向英特尔的 ifort 编译器团队提交票证，以获得可能的解决方案。