On Mon, 22 Aug 2016, Paul Leopardi wrote:
I am seeing a problem where "g.is_isomorphic(h)" is taking an inordinately
long time, where g and h are graphs, even though
"g.automorphism_group().order() == h.automorphism_group().order()", and
"g.canonical_label() == h.canonical_label()" both take a reasonable time.
Do you have Bliss installed? If so, then canonical_label() uses it, but
is_isomorphic() does not.
My main question for the moment is how do I specify graphs here in
sage-support so that others can reproduce the problem?
dig6_string() is only available do directed graphs, but a Graph made from
DiGraph is just a graph with directions forgotten. So you can say
DiGraph(g).dig6_string()
and on the other direction
Graph(DiGraph('DOOOW?'))
will give an undirected graph. We can then try to relabel your graph (like
g.relabel(lambda x: x+1) ) and check for isomorphism.
--
Jori Mäntysalo
