Permutation function for distance measure

Hi, i want to get the possible number of distance between k number of coordinate. Assume that we have 2 coordinate (k=2), then the possible distance are (1,2),(2,1). Thus the number of distance for k=2 is 2.

Another example is if k=3, the possible coordinate are (1,2),(1,3),(2,3),(2,1),(3,1),(3,2).

However, i also need to assume that distance between (1,2) and (2,1) is same. Thus if k=2, the possible coordinate is 1 and if k=3, possible coordinate is 3.

I had tried the permutation function in matlab, but it do not suitable , especially when k=3 as below.

Hope the explainantion is clear. Please help to suggest other suitable function or possible code. TQIA

v = [1 2 3];
P = perms(v)

the output:
P =

     3     2     1
     3     1     2
     2     3     1
     2     1     3
     1     3     2
     1     2     3

Answer 1

[KSSV]

You can get the distances between each pair using pdist. From this you can make decision.

v = [1 2 3];
P = perms(v)

d = pdist(P) 
Z = squareform(d)