Carlo, Thank you for reporting this. It is now a trac ticket:
http://trac.sagemath.org/sage_trac/ticket/1961 -- Robert M On Jan 27, 5:50 am, "Carlo Hamalainen" <[EMAIL PROTECTED]> wrote: > Hi, > > I have two graphs, g1 and g2 (defined below), for which > g1.is_isomorphic(g2) fails, but I know that they are isomorphic, and I > can apply a relabelling of the vertices of g1 so that > g1.is_isomorphic(g2) evaluates to True (see the code at the end of > this email). > > Have I set up something incorrectly? At first I wondered if vertices > have to be in the range 0..n (mine are on 1..n) but adding an isolated > vertex '0' doesn't change the behaviour of my code. > > Any ideas? > > -- > Carlo Hamalainenhttp://carlo-hamalainen.net > > # This file is athttp://carlo-hamalainen.net/sagetmp/graphiso.sage > > g1 = graphs.EmptyGraph() > g2 = graphs.EmptyGraph() > > g1.add_edges([(1, 17, None), (1, 21, None), (1, 25, None), (2, 17, > None), (2, 22, None), (2, 26, None), (3, 17, None), (3, 23, None), (3, > 27, None), (4, 17, None), (4, 24, None), (4, 28, None), (5, 18, None), > (5, 21, None), (5, 26, None), (6, 18, None), (6, 22, None), (6, 27, > None), (7, 18, None), (7, 23, None), (7, 28, None), (8, 18, None), (8, > 24, None), (8, 25, None), (9, 19, None), (9, 21, None), (9, 27, None), > (10, 19, None), (10, 22, None), (10, 28, None), (11, 19, None), (11, > 23, None), (11, 25, None), (12, 19, None), (12, 24, None), (12, 26, > None), (13, 20, None), (13, 21, None), (13, 28, None), (14, 20, None), > (14, 22, None), (14, 25, None), (15, 20, None), (15, 23, None), (15, > 26, None), (16, 20, None), (16, 24, None), (16, 27, None), (17, 29, > None), (18, 29, None), (19, 29, None), (20, 29, None), (21, 30, None), > (22, 30, None), (23, 30, None), (24, 30, None), (25, 31, None), (26, > 31, None), (27, 31, None), (28, 31, None)]) > > g2.add_edges([(1, 17, None), (1, 21, None), (1, 28, None), (2, 17, > None), (2, 22, None), (2, 25, None), (3, 17, None), (3, 23, None), (3, > 26, None), (4, 17, None), (4, 24, None), (4, 27, None), (5, 18, None), > (5, 21, None), (5, 26, None), (6, 18, None), (6, 22, None), (6, 27, > None), (7, 18, None), (7, 23, None), (7, 28, None), (8, 18, None), (8, > 24, None), (8, 25, None), (9, 19, None), (9, 21, None), (9, 27, None), > (10, 19, None), (10, 22, None), (10, 28, None), (11, 19, None), (11, > 23, None), (11, 25, None), (12, 19, None), (12, 24, None), (12, 26, > None), (13, 20, None), (13, 21, None), (13, 25, None), (14, 20, None), > (14, 22, None), (14, 26, None), (15, 20, None), (15, 23, None), (15, > 27, None), (16, 20, None), (16, 24, None), (16, 28, None), (17, 29, > None), (18, 29, None), (19, 29, None), (20, 29, None), (21, 30, None), > (22, 30, None), (23, 30, None), (24, 30, None), (25, 31, None), (26, > 31, None), (27, 31, None), (28, 31, None)]) > > perm = {0:0, 1: 13, 2: 14, 3: 15, 4: 16, 5: 5, 6: 6, 7: 7, 8: 8, 9: 9, > 10: 10, 11: 11, 12: 12, 13: 1, 14: 2, 15: 3, 16: 4, 17: 20, 18: 18, > 19: 19, 20: 17, 21: 21, 22: 22, 23: 23, 24: 24, 25: 25, 26: 26, 27: > 27, 28: 28, 29: 29, 30: 30, 31: 31} > > # This says no: > print g1.is_isomorphic(g2) > > # But I can find a vertex relabelling... > g1.relabel(perm) > # ... and this says yes: > print g1.is_isomorphic(g2) --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] 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 -~----------~----~----~----~------~----~------~--~---
