id summary reporter owner description type status priority milestone component resolution keywords cc merged author reviewer upstream work_issues branch commit dependencies stopgaps
15810 Immutable directed graphs should know that they are directed SimonKing "Bug:
{{{
sage: Q = DiGraph({1:{2:['a','b'], 3:['c']}, 2:{3:['d']}})
sage: Q.is_directed_acyclic()
True
sage: I = Q.copy(immutable=True)
sage: I.is_directed_acyclic()
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
in ()
----> 1 I.is_directed_acyclic()
/home/king/Sage/git/sage/local/lib/python2.7/site-packages/sage/graphs/digraph.pyc in is_directed_acyclic(self, certificate)
1117 False
1118 """"""
-> 1119 return self._backend.is_directed_acyclic(certificate = certificate)
1120
1121 def to_directed(self):
/home/king/Sage/git/sage/local/lib/python2.7/site-packages/sage/graphs/base/c_graph.so in sage.graphs.base.c_graph.CGraphBackend.is_directed_acyclic (sage/graphs/base/c_graph.c:19314)()
ValueError: Input must be a directed graph.
}}}" defect closed major sage-6.2 graph theory fixed immutable directed graph ncohen Nathann Cohen Simon King N/A d6ca86c1d6984bc7a468b80905ddec01323cc9b6 d6ca86c1d6984bc7a468b80905ddec01323cc9b6 #15623