graph_editor(p) should work for p a poset

[rlmill]

Obviously graph_editor(p) doesn't work on its own, since p is not a graph. However, it should be possible to implement a few functions for p to make this work:

File "sage/graphs/graph_editor.py", line 111, in graph_editor
    if not isinstance(graph.get_pos(), dict):
AttributeError: 'FinitePoset' object has no attribute 'get_pos'

While wishing, it would also be nice if the graph editor could be adapted to remember vertex labels, at least in the case that the labels are strings.

Depends on #30540

CC: @saliola @rkirov @qed777

Component: combinatorics

Issue created by migration from https://trac.sagemath.org/ticket/8016

[jm58660]

comment:1

If the name of variable to save the (undirected) graph is P, then it is easy to just say

d = DiGraph()
d.add_vertices(P.vertices())
pos = P.get_pos()
for e in P.edges(labels=False):
    if pos[e[0]][1] < pos[e[1]][1]:
        d.add_edge(e)
    else:
        d.add_edge([e[1], e[0]])
P = Poset(d).canonical_label()

to convert it to poset. But really somebody should expand the code to handle digraphs.

[slel]

comment:2

Somewhat related:

• Add to_digraph method to Permutation #30214: Add to_digraph method to Permutation

[slel]

Dependencies: #30540