why two indexes in 1d cell array ? (octave-3.4.2) ... how about more dimensions ?

[Sergei Steshenko]

Hello,

reading 
http://www.gnu.org/software/octave/doc/interpreter/Cell-Arrays.html#Cell-Arrays

I see this:

"
A cell array is a container class able to do just that. In general cell arrays 
work just like N-dimensional arrays with the exception of the use of ‘{’ and 
‘}’ as allocation and indexing operators. 
"

- mu understanding of "N-dimensional arrays" is that number of dimensions is
set as needed when user creates a cell array.

Reading on

http://www.gnu.org/software/octave/doc/interpreter/Basic-Usage-of-Cell-Arrays.html#Basic-Usage-of-Cell-Arrays

I see:

"
c = {"a string", rand(2, 2)};
",

I decided to further try this example:

"
octave:1> c = {"a string", rand(2, 2)}
c =
{
  [1,1] = a string
  [1,2] =

     0.245929   0.096505
     0.018941   0.231544

}
octave:2> size(c)
ans =

   1   2

octave:3> c{1:2}
ans = a string
ans =

   0.245929   0.096505
   0.018941   0.231544

octave:4> celldisp(c)
c{1} =

a string

c{2} =

   0.245929   0.096505
   0.018941   0.231544

octave:5> 
".

Questions/statements

1) in

"

c =
{
  [1,1] = a string
  [1,2] =
"

I see _two_ indexes, i.e. "[1,1]...", "[1,2]", though to me it looks like
created a _1d_ (just _one_ dimension) cell array;


2) in

"
octave:4> celldisp(c)
c{1} =

a string

c{2} =

   0.245929   0.096505
   0.018941   0.231544

octave:5>   
"

I see just _one_ index ("c{1}...", "c{2}...".

So, why the discrepancy, i.e. in one case two indexes, and in the other
one ?

Why no indexes at all in

"
octave:3> c{1:2}
ans = a string
ans =

   0.245929   0.096505
   0.018941   0.231544
" ?
...
Another example:

"
octave:5> b = {1, 2, 3}
b =
{
  [1,1] =  1
  [1,2] =  2
  [1,3] =  3
}
octave:6>   
"
- there is _nothing_ 2d inside "b" - why still _two_ indexes ?

...

Can anybody please explain this:

"
octave:10> g{1,1,1,1} = 6
g =
{
  [1,1] =  6
}
octave:11> celldisp(g, "g")
g{1} =

 6

octave:12> 
"

?

I.e. _definitely_ a 4-d array shows just two indexes in

"
octave:10> g{1,1,1,1} = 6
g =
{
  [1,1] =  6
}
"

and at all just _one_ index in

"
octave:11> celldisp(g, "g")
g{1} =

 6
".
...
I continue with that "g" cell array:
"
octave:12> g{1,1,1,2} = 7
g = {1x1x1x2 Cell Array}
octave:13> celldisp(g, "g")
g{1} =

 6

g{2} =

 7

octave:14> 
".

...

An equivalent example with a matrix:
"
octave:14> gm(1,1,1,1) = 5
gm =  5
octave:15> gm(1,1,1,2) = 6
gm =

ans(:,:,1,1) =  5
ans(:,:,1,2) =  6

octave:16> gm
gm =

ans(:,:,1,1) =  5
ans(:,:,1,2) =  6

octave:17> 
"

- makes more sense to me (i.e. I see all four dimensions), but not quite - 
the ':' seems to be strange.

...

Oh-oh, with matrices there seem to be problems too, I'll write a
separate Email.

Is this all expected and documented behavior ?

Thanks,
  Sergei.