Jason,
I've been working with nonisomorphic colorings recently. I use the following:
def canonical_coloring_label(G,c):
"""
Given a coloring dictionary,
{color1 : [u1, u2, ...], color2 : [v1, v2, ... ], ... }
return a string which uniquely identifies the isomorphism
class of the coloring.
"""
H = G.copy()
for i in c:
H.add_edges([(i,j) for j in c[i]])
P = [G.vertices(), c.keys()]
return H.canonical_label(partition=P).graph6_string()
I agree, it'd be nice to not have to do this. I've been talking with
Robert Miller to use the new canonical augmentation code to generate
nonisomorphic colorings.
With colorings, embeddings, and matchings, I wonder: should we create
classes to represent these objects instead of passing around naked
data structures? Then, it would make a lot of sense to have things
like coloring1.is_isomorphic(coloring2).
On Fri, Jan 6, 2012 at 7:42 AM, Nathann Cohen <nathann.co...@gmail.com> wrote:
> And if you accept to sligthly change the graph, you can add a universal
> vertex v to it. If u is of color red, color edge uv with red, and the same
> for all vertices. Do this in both graph and all will be fine :-)
>
> Nathann
>
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