The issue is that the graph is not seen as weigthed by default. So either you provide a weight function, or you have to set the graph has weigthed. Then you get what you expect.
sage: G = Graph([(0,1,78), (0,2,99), (0,5,20), (1,3,16), (1,6,68), (1,7,34), (2,4,43), (2,5,13), (3,4,70), (3,7,2), (4,5,76), (4,7,77), (5,7,31), (6,7,74 )]) sage: G.weighted() False sage: E = G.min_spanning_tree() sage: print(sum(e[2] for e in E), E) (391, [(0, 1, 78), (0, 2, 99), (0, 5, 20), (1, 3, 16), (1, 6, 68), (1, 7, 34 ), (4, 5, 76)]) sage: E = G.min_spanning_tree(weight_function=lambda e:e[2]) sage: print(sum(e[2] for e in E), E) (193, [(0, 5, 20), (1, 3, 16), (1, 6, 68), (2, 4, 43), (2, 5, 13), (3, 7, 2 ), (5, 7, 31)]) sage: G.weighted() False sage: G.weighted(True) sage: G.weighted() True sage: E = G.min_spanning_tree() sage: print(sum(e[2] for e in E), E) (193, [(0, 5, 20), (1, 3, 16), (1, 6, 68), (2, 4, 43), (2, 5, 13), (3, 7, 2 ), (5, 7, 31)]) Le mardi 5 décembre 2017 02:38:39 UTC+1, fco...@uea.edu.br a écrit : > > Hello. > > Apparently, min_spanning_tree is not operating properly (see > printscreens). Manually, the result is 193. I tried several algorithms and > the error persists. Or am I wrong? > > Regards, > Flávio. > > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
