Understanding problem doc fix property/global

Hello everybody,

I'm a little bit confused about the doc of the fix property/global.

In the example the style-arg for atomtypepair "nCol" is set to 2 and the number of defaultvalues is 6, which are mapped into a matrix like
[1 2
3 4
5 6]
In my understanding, the elements in the diagonal elements of the matrix represent the parameter for the interaction within one type of atoms and the other elements of the matrix define the interaction between two types of atoms. If there are 2 types of atoms, the Matrix should be a 2x2-Matrix, and if there are 3 types of atoms, the Matrix should be a 3x3-Matrix. It's always a quadratic matrix...

Therefore for me, it doesn't make sense to define a matrix with 6 elements - or did I get anything wrong?

Thanks in advance,
kind regards,

Sebastian