Array index bug....

[steinhh(at)ulrik.uio.no (Stein Vidar Hagfors Haugan)]

Try this:

  data = transpose([[[dist(50)]],[[dist(50)]]],[2,0,1])
  help,data
  ; DATA            FLOAT     = Array[2, 50, 50] 

  tvscl,data(0,*,*) ;; Shows the expected image...

But, imagine that you're writing a general program that must
accept arrays with any number of dimensions, and extract data
from the array in (n-1)-dimensional "slices" like the
above. Short of having a CASE statement for every extraction
of data from the array, the way to do this is e.g.:

  tvscl,data(0,*,*,*,*)  ;; Shows the expected image in this case, 
                         ;; works for up to 5 dimensions (though
                         ;; I don't know what TVSCL would say about
                         ;; that!)

Now, IDL *claims* to handle up to 8 dimensions, so one would think
the best thing is to prepare your code for it, e.g.:

  tvscl,data(0,*,*,*,*,*,*,*)

The image is *not* what you expect! Clearly something breaks
down with the eighth dimension.....

Another matter is, how do you create e.g., 4-dimensional data
sets with the concatenation style? Lets see:

IDL> help,[1,2] 
<Expression>    INT       = Array[2] 
IDL> help,[[1],[2]] 
<Expression>    INT       = Array[1, 2] 
IDL> help,[[[1]],[[2]]] 
<Expression>    INT       = Array[1, 1, 2] 
IDL> help,[[[[1]]],[[[2]]]] 
 
help,[[[[1]]],[[[2]]]] 
                      ^ 
% Only eight levels of variable concatenation are allowed. 

Hmm. Very strange indeed, since I don't even have 8 opening
(or closing) brackets in total, much less anything going to
what *I* would interpret as 8 levels of concatenation....

Regards,

Stein Vidar