[Nauty] Isomorphism with coloured multigraphs

[Parker Jones]

Chris,

> > I'd like to check for isomorphism between coloured multigraphs.
> > Reading through previous posts I understand that multiple edges are
> > denoted by colouring/partitioning - implying it's not possible to have
> > colouring and multi-edges at the same time. Is this really the case?
> >
>Nope, I've done directed coloured multigraphs :)
>
>The "trick" is to have lots of colours in the generated graphs. Use some
>for the nodes, some for the multiple edges and (in my case) some for the
>directions. Assuming you make each of these sets distinct the everything
>should be fine :)

Thanks for the quick reply and the good news.  I'm trying to understand your 
approach but don't quite get it.

Given a simple multigraph, say
a - b = c     with colouring red = {a} and blue = {b,c}

I'd represent this as:
0: 1;
1: 2.

Now suppose we define four 'colours' as follows:
  1 arc    red
  2 arcs   red
  1 arc    blue
  2 arcs   blue

Now how can we represent the colouring and the numbers of edges?

f=[...] ?

Alternatively, if you could post one of your directed multigraphs that would 
be great.

Thanks,

P.J.

_________________________________________________________________
Surf the net and talk on the phone with Xtra JetStream @  
http://xtra.co.nz/jetstream