递归调用出错，error #7121

bfjc

[Fortran] syntaxhighlighter_viewsource syntaxhighlighter_copycode

      type octree_node
      type(point), dimension(:), pointer :: points
      type(octree_node), dimension(:), pointer :: children
      real :: x_min, x_max, y_min, y_max, z_min, z_max
      integer :: num_points
      end type octree_node

      Contains
      recursive subroutine build_octree(node, points, x_min, x_max, &
          y_min, y_max, z_min, z_max)
      type(octree_node), pointer :: node
      type(point), dimension(:), pointer :: points
      real, intent(in) :: x_min, x_max, y_min, y_max, z_min, z_max
      integer :: i, j, k, num_points, num_children
      real :: x_mid, y_mid, z_mid

      do k = 0, 1
        do j = 0, 1
          do i = 0, 1
            num_children = num_children + 1
            allocate(node%children(num_children))
            call build_octree(node%children(num_children), points,&                     !这里报错，error #7121: A ptr dummy may only be argument associated with a ptr, and this array element or section does not inherit the POINTER attr from its parent array.   [CHILDREN]
              x_min + i*(x_mid - x_min), x_min + (i+1)*(x_mid - x_min),&
              y_min + j*(y_mid - y_min), y_min + (j+1)*(y_mid - y_min),&
              z_min + k*(z_mid - z_min), z_min + (k+1)*(z_mid - z_min))
          end do
        end do
      end do

      end subroutine build_octree

这里截取了一部分问题代码，在递归调用函数时第一个变量出现了问题，如果第一个变量改为node则可以运行，是因为node%children(num_children)不是指针吗，不太明白，希望大佬们帮忙看看。

fcode

node%children 的类型虽然为  type(octree_node), dimension(:), pointer :: children 是指向数组的指针。
但 node%children(num_children) 表示 node%children 指针指向目标的第 num_children 个元素。
因为 node%children 指向的目标类型是 type(octree_node), dimension(:)，所以它的第 num_children 个元素，类型为 type(octree_node) 而不是 type(octree_node), pointer

有两种修改方法，我推荐第一种
一，第11行，由 type(octree_node), pointer :: node 修改为 type(octree_node) :: node
二，build_octree 函数中增加一个指针变量 type(octree_node), pointer :: pNode，在 call build_octree(pNode 时传入，传入之前先 pNode => node%children(num_children)

由于Fortran是默认传地址的，所以除非你要在子程序中分配指针，否则没有什么必要把虚参定义为指针。

bfjc

好的好的，谢谢刘涛。