'combnk' enumeration of combinations

Hi,

If I use 'combnk' in a all positive region, it gives me all the possible combinations.

>> c = combnk(1:3,2)

c =

     1     2
     1     3
     2     3

However, if I use 'combnk' in a negative-to-positive region, it only gives me one combination.

>> c = combnk(-1:1,3)

c =

    -1     0     1

What I really like to obtain is something below with all the combinations.

  -1  -1  -1
  -1  -1   0
  -1  -1   1
  -1   0  -1
  -1   0   0
  -1   0   1
  -1   1  -1
  -1   1   0
  -1   1   1
   0  -1  -1
   0  -1   0
   0  -1   1
   0   0  -1
   0   0   0
   0   0   1
   0   1  -1
   0   1   0
   0   1   1
   1  -1  -1
   1  -1   0
   1  -1   1
   1   0  -1
   1   0   0
   1   0   1
   1   1  -1
   1   1   0
   1   1   1

How to achieve it? Should I not use 'combnk' but something else instead?

Please can you help?

Answer 1

[Stephen23]

>> [X,Y,Z] = ndgrid([-1,0,1]);
>> M = [Z(:),Y(:),X(:)]
M =
  -1  -1  -1
  -1  -1   0
  -1  -1   1
  -1   0  -1
  -1   0   0
  -1   0   1
  -1   1  -1
  -1   1   0
  -1   1   1
   0  -1  -1
   0  -1   0
   0  -1   1
   0   0  -1
   0   0   0
   0   0   1
   0   1  -1
   0   1   0
   0   1   1
   1  -1  -1
   1  -1   0
   1  -1   1
   1   0  -1
   1   0   0
   1   0   1
   1   1  -1
   1   1   0
   1   1   1