On Sat, Jun 27, 2020 at 10:35 AM 赵日天 <a1345654324567...@gmail.com> wrote: > > While running the code > > for g in graphs(): > print(g.is_line_graph()) > > Sage returns the error message, after lots of True-s and False-s: > > --------------------------------------------------------------------------- > Exception Traceback (most recent call last) > <ipython-input-6-a5cd36160d42> in <module>() > 1 for g in graphs(): > ----> 2 print(g.is_line_graph()) > 3 > > /opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/graphs/line_graph.pyx > in sage.graphs.line_graph.is_line_graph > (build/cythonized/sage/graphs/line_graph.c:2286)() > 220 if g.is_connected(): > 221 try: > --> 222 R, isom = root_graph(g) > 223 if certificate: > 224 return True, R, isom > > /opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/graphs/line_graph.pyx > in sage.graphs.line_graph.root_graph > (build/cythonized/sage/graphs/line_graph.c:7147)() > 621 > 622 if not is_isom: > --> 623 raise Exception(error_message) > 624 > 625 return R, isom > > Exception: It looks like there is a problem somewhere. Youfound a bug here ! > Please report it on sage-devel,our google group ! > > What's the bug here?
A bug in is_line_graph() has recently been fixed here: https://trac.sagemath.org/ticket/29740 This fix should be in Sage 9.2.beta2 > > -- > 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 view this discussion on the web visit > https://groups.google.com/d/msgid/sage-devel/e2941e84-c1f8-48f5-adea-7a0b18353868o%40googlegroups.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 sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/CAAWYfq3PxOw6NFG%2Bw6ThMByDm9jW-LrA49ORT7BVqZRgF1ZOtA%40mail.gmail.com.
