[with patch, with positive review] length of DAGs with loops calculation runs infinite

[schilly]

G4 has a loop: 2->4 and 4->2

G4 = DiGraph({1:[2,2,3,5], 2:[3,4], 3:[4], 4:[2,5,7], 5:[6]}, multiedges=True)
G4_path.count()

RuntimeError: maximum recursion depth exceeded

There are related issues calulating incoming_paths and possibly more in sage.combinat.graph_path!

[schilly]

ah, solution is very simple: just check if G4.is_directed_acyclic() is true ;)

[rlm]

Could you be more specific? I have no idea what G4_path is. Also, could you post a full traceback?

[ncalexan]

Code looks good, docstrings and tests seem appropriate.

[mabshoff]

Merged in Sage 2.10.1.alpha1