kcrisman wrote: > Using Sage 2.8.12 (attempted on the notebook servers with current > version, but the one my account is one is sagenb.org and never gave an > output at all), the following behavior happens: > > sage: L = list(graphs(3, lambda H: H.size() <=3)) > sage: len(L) > 8 > > Yet, > > sage: L = list(graphs(3, lambda H: H.size() ==3)) > sage: len(L) > 0 > > even though > > sage: for G in L: print G.size() > 0 > 0 > 0 > 0 > 1 > 2 > 1 > 3 > > But, interestingly, > > sage: L = list(graphs(3, lambda H: H.size() !=3)) > sage: len(L) > 7 > > > I assume this is a bug, but because I don't understand > canaug_traverse, I am not certain. Thanks for any clarification! > Apologies in advance if this was already fixed and I didn't get it due > to lackadaisical upgrades.
Under Sage 2.9.3: sage: L = list(graphs(3, lambda H: H.size() <=3)) sage: len(L) 4 sage: L = list(graphs(3, lambda H: H.size() ==3)) sage: len(L) 0 sage: for G in L: print G.size() ....: sage: L = list(graphs(3, lambda H: H.size() !=3)) sage: len(L) 3 This seems to match the documentation, which says that with the default options, if the test function has the property that if a graph passes the test, then every subgraph obtained by deleting edges also passes the test, then you will get a complete listing of all graphs which satisfy the test function. Thus the results in Sage 2.9.3 correctly indicate that there are 4 graphs with size <=3. Because the maximum number of edges is 3 on 3-vertex graphs, the last example also correctly calculates that there are 3 graphs with size < 3. However, the generating method does not guarantee that the second example (size==3) will produce all graphs with exactly 3 edges. It is interesting that you get different numbers (8, 0, and 7 compared to 4, 0, and 3). Jason --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@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-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
