Open 6bdad4c1-1e26-4f2f-a442-a01a2292c181 opened 12 years ago
The dense graph code doesn't support edge labeling, but the code in point_configuration.py rely on this. Maybe it is a mistake that dense_graph doesn't crash and burn whenever someone call add_edge(u, v, nonNone) -- but it is consistent with cases like
sage: G=Graph(multiedges=False)
sage: G.add_edge(0,1)
sage: G.add_edge(0,1)
sage: G.edges()
[(0, 1, None)]
I wrote the code for polyhedra. It is definitely a bug if the graph silently gives the wrong answer just because some backend doesn't support edge labels.
I started #12540 for this discussion.
I will investigate further if the lack of edge labels is the only source of the wrong results we spotted in #12318.
We discovered in #12318 that some functions of sage/geometry/polyhedra and sage/geometry/triangulation/point_configuration.py return wrong results if Graph(sparse = True) is replaced by Graph(sparse = False)
CC: @sagetrac-brunellus @rlmill
Component: graph theory
Issue created by migration from https://trac.sagemath.org/ticket/12387