Question

是否可以在Fortran 90中定义具有非连续索引的数组？

以下代码返回错误（Error: The module or main program array 'test' at (1) must have constant shape）：

program example
  implicit none
  integer, dimension((/1,3/)) :: test
end

是否有另一种方法来定义这样的数组，或者这是不允许的？

Answer 1

您可以自己实施该类型。这是一种混乱而低效的方式。

module WeirdArray
  implicit none
  private

  type, public :: Warray
    private
    integer, dimension(:), allocatable :: indeces
    real, dimension(:), allocatable :: vals
  contains
    procedure, pass :: init
    procedure, pass :: get
    procedure, pass :: set
  end type

contains
  subroutine init(this, i, v)
    class(warray), intent(out) :: this
    integer, dimension(:) :: i
    real, dimension(size(i)) :: v
    this%indeces = i
    this%vals = v
  end subroutine init

  function get(this, indx) result(x)
    class(warray), intent(in) :: this
    integer, intent(in) :: indx
    real :: x
    integer, dimension(:), allocatable :: p
    integer :: i
    p = pack([(i,i=1,size(this%indeces))],this%indeces==indx)
    x = this%vals( p(1) )
  end function get

  subroutine set(this, indx, x)
    class(warray), intent(inout) :: this
    integer, intent(in) :: indx
    real, intent(in) :: x
    integer, dimension(:), allocatable :: p
    integer :: i
    p = pack([(i,i=1,size(this%indeces))],this%indeces==indx)
    this%vals( p(1) ) = x
  end subroutine set  

end module WeirdArray

你可以像这样使用它：

program main
  use weirdArray
  implicit none

  type(Warray) :: wa

  call wa%init([5,12], [10.0, 24.0])

  write(*,*) wa%get(5)
  call wa%set(5, 3.14)
  write(*,*) wa%get(5)
  write(*,*) wa%get(12)

end program main

在Fortran中定义具有非连续索引的数组

1 个答案: