from typing import List, Optional, Tuple
def _draw_pag_edges(
dot,
directed_edges: List[Tuple] = None,
circle_edges: List[Tuple] = None,
undirected_edges: List[Tuple] = None,
bidirected_edges: List[Tuple] = None,
**attrs,
):
"""Draw the PAG edges.
PAG edges may have different endpoints.
"""
# keep track of edges with circular edges between each other because we want to
# draw edges correctly when there are circular edges
found_circle_sibs = set()
# draw all possible causal edges on a graph
if circle_edges is not None:
for sib1, sib2 in circle_edges:
# memoize if we have seen the bidirected circular edge before
if f"{sib1}-{sib2}" in found_circle_sibs or f"{sib2}-{sib1}" in found_circle_sibs:
continue
found_circle_sibs.add(f"{sib1}-{sib2}")
# set directionality of the edges
direction = "forward"
# check if the circular edge is bidirectional
if (sib2, sib1) in circle_edges:
direction = "both"
arrowtail = "odot"
elif directed_edges is not None and (sib2, sib1) in directed_edges:
direction = "both"
arrowtail = "normal"
sib1, sib2 = str(sib1), str(sib2)
dot.edge(
sib1,
sib2,
arrowhead="odot",
arrowtail=arrowtail,
dir=direction,
color="green",
**attrs,
)
if undirected_edges is not None:
for neb1, neb2 in undirected_edges:
neb1, neb2 = str(neb1), str(neb2)
dot.edge(neb1, neb2, dir="none", color="brown", **attrs)
if bidirected_edges is not None:
for sib1, sib2 in bidirected_edges:
sib1, sib2 = str(sib1), str(sib2)
dot.edge(sib1, sib2, dir="both", color="red", **attrs)
return dot, found_circle_sibs
[docs]def draw(
G,
direction: Optional[str] = None,
pos: Optional[dict] = None,
name: Optional[str] = None,
shape="square",
**attrs,
):
"""Visualize the graph.
Parameters
----------
G : pywhy_nx.MixedEdgeGraph
The mixed edge graph.
direction : str, optional
The direction, by default None. See: https://graphviz.org/docs/attrs/rankdir/.
pos : dict, optional
The positions of the nodes keyed by node with (x, y) coordinates as values.
By default None, which will
use the default layout from graphviz.
name : str, optional
Label for the generated graph.
shape : str
The shape of each node. By default 'square'. Can be 'circle', 'plaintext'.
attrs : dict
Any additional edge attributes (must be strings). For more
information, see documentation for GraphViz.
Returns
-------
dot : graphviz.Digraph
DOT language representation of the graph.
"""
from graphviz import Digraph
# make a dict to pass to the Digraph object
g_attr = {"label": name}
if name is not None:
dot = Digraph(graph_attr=g_attr)
else:
dot = Digraph()
# set direction from left to right if that's preferred
if direction == "LR":
dot.graph_attr["rankdir"] = direction
circle_edges = None
directed_edges = None
undirected_edges = None
bidirected_edges = None
if hasattr(G, "circle_edges"):
circle_edges = G.circle_edges
if hasattr(G, "directed_edges"):
directed_edges = G.directed_edges
if hasattr(G, "undirected_edges"):
undirected_edges = G.undirected_edges
if hasattr(G, "bidirected_edges"):
bidirected_edges = G.bidirected_edges
# draw PAG edges and keep track of the circular endpoints found
dot, found_circle_sibs = _draw_pag_edges(
dot,
directed_edges,
circle_edges=circle_edges,
undirected_edges=undirected_edges,
bidirected_edges=bidirected_edges,
)
if hasattr(G, "get_graphs"):
directed_G = G.get_graphs("directed")
else:
directed_G = G
for v in G.nodes:
child = str(v)
if pos and pos.get(v) is not None:
dot.node(child, shape=shape, height=".5", width=".5", pos=f"{pos[v][0]},{pos[v][1]}!")
else:
dot.node(child, shape=shape, height=".5", width=".5")
for parent in directed_G.predecessors(v):
if parent == v or not directed_G.has_edge(parent, v):
continue
# memoize if we have seen the bidirected circular edge before
if f"{child}-{parent}" in found_circle_sibs or f"{parent}-{child}" in found_circle_sibs:
continue
parent = str(parent)
if parent == v:
dot.edge(parent, child, style="invis", **attrs)
else:
dot.edge(parent, child, color="blue", **attrs)
return dot