It could be an integer overflow somewhere in the determinant computation, as the numbers are very, very big.
By default, determinants are computed by flint, so it can be a bug there. You can modify the code of spanning_trees_count() to allow passing of the algorithm to compute determinant, and see if you can get it right. HTH Dima On Sun, Jun 18, 2023 at 8:49 AM Georgi Guninski <[email protected]> wrote: > > On Sun, Jun 18, 2023 at 10:16 AM Emmanuel Briand > <[email protected]> wrote: > > > > Have you taken into account the following? > > > > ignature: G1.spanning_trees_count(root_vertex=None) > > Docstring: > > Return the number of spanning trees in a graph. > > > > In the case of a digraph, counts the number of spanning out-trees > > rooted in "root_vertex". Default is to set first vertex as root. > > > > > > Thanks, I should have RTFM. > > This still doesn't work for me: > > sage: > G1.spanning_trees_count(root_vertex=None),G2.spanning_trees_count(root_ver > ....: tex=None) > (27202601182632270746156805986464038912000, > 40803901773948406119235208979696058368000) > > > Is it rigorous to set c1=G1.spanning_trees_count() > and then do: > > sage: c1=G1.spanning_trees_count() > sage: for i in range(G1.order()): > ....: c2=G2.spanning_trees_count(i) > ....: if c2==c1: print(i) > ....: > 6 > > I expect for isomorphic multi digraphs the loop to find equal c1,c2? > > -- > 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 [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-devel/CAGUWgD_Zkf7g2py2PxWkYA4PqBOW6Ws%2BW31JtsQF2nmO6JE9tg%40mail.gmail.com. -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/CAAWYfq2%2B_eejUwRr9M5%3DB%3Ddn36XMvU1hRbEQ_wwGu2obdWf2Kw%40mail.gmail.com.
