Realize an array which the second dimension depends on the first argument

Question

Suppose I have an array A[a,b]. The dimension of a is 2. When a=1, the dimension of b is 3; when a=2, the dimension of b is 6.

For example, one array A looks like

[[1,2,3]
[4,5,6,7,8,9]]

it is combined from 1*3 and 1*6. In total 9 entries, not from input.

Is there any method to define such an array in Fortran? or I need other type of data structure?

Also see the comments at https://stackoverflow.com/questions/49304186/append-to-3d-array-to-enable-first-dimensions-differing-in-length-among-the-3rd?noredirect=1&lq=1 — Vladimir F Героям слава, May 26 '21 at 06:56

score 2 · Accepted Answer · answered May 26 '21 at 01:40

2

You need to provide a better description of what you want to do. With allocatable entities you can trivially achieve what you have described.

program foo
  integer a, b
  real, allocatable :: x(:,:)
  read(*,*) a
  if (a == 1 .or. a == 2) then
     b = 3 * a
     allocate(x(a,b))
   else
     stop 'Is this right?'
  end if
  x = 1
  print *, shape(x)
end program foo

answered May 26 '21 at 01:40

steve

657
1
4
7

edited. sorry for the confusing. – AlphaF20 May 26 '21 at 02:33

Realize an array which the second dimension depends on the first argument

1 Answers1

Linked