[Nauty-list] The concept of indicator function

[Roger Ting]

I am currently mulling over the concept of indicator function. Why do we 
need an indicator function when we can select canonical label by 
ordering the terminal partition using the graph adjacency matrix?
Can anyone explain to me the whole concept of indicator function? All i 
understand now it is used in the selection one of the terminal node as 
canonical label. Thanks.