[Nauty] canonical label for directed graphs

[Edward N Turner]

Thanks for the pointers so far..

The adjacency matrix of directed graphs may not be symmetric, as opposed
to symmetric adj matrices for undirected graphs, which always are. By
considering the whole adj matrix during computation of the canonical
label, would we have a way of computing canonical labels of directed
graphs without any need for converting them to undirected ones in the
first place, or not?

Cheers, Edward.