Can we convert a vector into a similarity matrix ?

I have a vector of size 1x40000 and I want to know if it is possible to compute "its" similarity matrix with Matlab

[KSSV]

What is similiarity matrix?

[John D'Errico]

Only you know what you mean by a similarity matrix in this context. So if you want help, you need to explain what you need. A broad name is not sufficient.

[Mayssa]

Similarity matrix = A symmetric matrix (M=M') which entries tell us how much similar each pair is. I should've used the term symmetric.