On Dec 14, 12:41 pm, fidelbc <fidel.barr...@gmail.com> wrote: > Here it is, ticket number 12155.
Thanks. > G=copy(self) > > Maybe here is where the bipartite property gets transferred to G. I'd say so. > If my counting is right, there are only 8 bipartite graphs whose > complements are also bipartite (and each of them has at most 4 > vertices). Would it be useful to preserve the bipartiteness property > when taking complement in any of these instances? If so, maybe > implement this in the BipartiteGraph complement method. That's a good thing to think about, but with so few graphs, and all so tiny, it doesn't strike me as worth the effort or the side effect of returning objects of slightly varying types. > I am also > thinking that the complement method in the BipartiteGraph could just > do something like > > return Graph(self.edges()).complement() Note the following alternative, which has the bonus of preserving some of the naming of the graph. This would at least fix the bug. sage: G=graphs.CompleteBipartiteGraph(3,3) sage: Graph(G).complement() complement(Complete bipartite graph): Graph on 6 vertices sage: Graph(G.edges()).complement() complement(): Graph on 6 vertices However, in either case it seems very inefficient to create all of the original edges, just to turn around and destroy them all right away. I'm not finding a method that converts a BipartiteGraph into a Graph with very little overhead. Maybe the present example illustrates the need for such a thing. Rob -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
