I think I know where is the problem. I have tried to reimplemente the function max, and I've see that it doesn't terminate when there is a comparaison between two complex conjugates.
The bug with max comes from a bug in the comparaison of two elements of QQbar : it should detect when two algebraic numbers are equals, but it doesn't and so it try to compute with more and more precision to see which one is greater, but it doesn't terminates because there are equals. Maybe I will try to fix this. Paul Le dimanche 30 mars 2014 16:00:14 UTC+2, Paul Mercat a écrit : > > If I do what you propose, it works. > But I want the maximum of the list in QQbar, not in RR, and I don't > understand why the max function take all this time. > And it also doesn't work with key=abs. > > Paul > > Le dimanche 30 mars 2014 15:49:45 UTC+2, John Cremona a écrit : >> >> m is an integer matrix and its eigenvalues (which are not all rel >> anyway) are returned as algebraic numbers (try e[0].parent()). >> >> Perhaps you want this: >> sage: max([RR(ei) for ei in e if ei in RR]) >> 1.99801167774722 >> >> but note that only 22 of the 38 eigenvalues are real. >> >> John >> >> >> On 30 March 2014 14:32, Paul Mercat <mer...@yahoo.fr> wrote: >> > The function max sometimes doesn't work in sage. >> > Here is an example : >> > >> > sage: a = Automaton([(0, 0, 0), (0, 1, 1), (1, 1, 1), (1, 2, 0), (2, 0, >> 0), >> > (2, 3, 1), (3, 4, 1), (3, 7, 0), (4, 1, 1), (4, 5, 0), (5, 0, 0), (5, >> 6, 1), >> > (6, 7, 0), (6, 37, 1), (7, 3, 1), (7, 8, 0), (8, 0, 0), (8, 9, 1), (9, >> 2, >> > 0), (9, 10, 1), (10, 2, 0), (10, 11, 1), (11, 2, 0), (11, 12, 1), (12, >> 13, >> > 0), (12, 34, 1), (13, 14, 0), (13, 24, 1), (14, 1, 1), (14, 15, 0), >> (15, 16, >> > 0), (15, 33, 1), (16, 0, 0), (16, 17, 1), (17, 1, 1), (17, 18, 0), (18, >> 3, >> > 1), (18, 19, 0), (19, 1, 1), (19, 20, 0), (20, 1, 1), (20, 21, 0), (21, >> 22, >> > 0), (21, 31, 1), (22, 23, 0), (23, 0, 0), (23, 24, 1), (24, 4, 1), (24, >> 25, >> > 0), (25, 26, 1), (25, 29, 0), (26, 7, 0), (26, 27, 1), (27, 1, 1), (27, >> 28, >> > 0), (28, 6, 1), (28, 19, 0), (29, 0, 0), (29, 30, 1), (30, 10, 1), (30, >> 18, >> > 0), (31, 2, 0), (31, 32, 1), (32, 2, 0), (32, 3, 1), (33, 2, 0), (33, >> 17, >> > 1), (34, 35, 1), (35, 1, 1), (35, 36, 0), (36, 16, 0), (36, 26, 1), >> (37, 5, >> > 0), (37, 11, 1)]) >> > sage: m = a.graph().adjacency_matrix() >> > sage: e = m.eigenvalues() >> > sage: print e >> > sage: max(e) #doesn't terminate !!! >> > >> > Do you know why it doesn't work ? >> > >> > Paul >> > >> > -- >> > 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+...@googlegroups.com. >> > To post to this group, send email to sage-...@googlegroups.com. >> > Visit this group at http://groups.google.com/group/sage-devel. >> > For more options, visit https://groups.google.com/d/optout. >> > -- 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 http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
