Stephen Hartke wrote: > On Wed, Apr 23, 2008 at 6:20 PM, Jason Grout > <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote: > > I have a need to enumerate all possible black and white colorings of a > graph, up to (colored) isomorphism. Is there a way to use some of the > NICE code to make this fast? It seems like I read somewhere that Robert > was going to generalize NICE to let you compute enumeration/canonical > things for more general combinatorial objects. > > > Jason, > > Is your graph highly symmetric? If not, then there's really no need to > worry about isomorph rejection (the only isomorphism being switching the > colors). If so, then McKay's method of "canonical augmentation" would be > helpful. McKay has a paper called "Isomorph-free exhaustive generation" > describing this that is available on his webpage.
Thanks. I've started reading that paper several times off and on through the past few years. I don't have just one graph; I want to do this for lots of graphs (i.e., let the user put in the graph). > > You can use NICE to do the actual isomorph testing, but you would need > to build the general framework yourself. I don't think this could be > done in general, since each type of combinatorial generation would need > different routines, and the "framework" part would be just a few lines. Thanks; that answers my question. As a separate issue, it'd be nice if there was some sort of callback function options (something like the callbacks that nauty supports) that was used in NICE. Thanks, Jason --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
