How to build these vectors?

I want to build all vector P's satisfying this: P=[p1 p2 ... pk] pi=1,...,N ,i=1,...,k for i>j : pi > pj Note that I know how to build them using k for loops. I need a code which is useful for all pairs of (N,k) Thanks

Answer 1

[Jan]

Do you mean something like: FEX: VChooseK?

[Mahdi]

I tried to use that but I didn't get anything. I mean for example (N,k)=(5,3) it produces all of these vectors: [1 2 3] [1 2 4] [1 2 5] [1 3 4] [1 3 5] [1 4 5] first element is fixed to one.

[Jan]

Why is the first element fixed? I'd expect:

R = VChooseK(1:5,3)
R = [1     2     3
     1     2     4
     1     2     5
     1     3     4
     1     3     5
     1     4     5
     2     3     4
     2     3     5
     2     4     5
     3     4     5]

"I didn't get anything" does not allow to provide assistance.