Source code for cfpq_data.graphs.utils.add_reverse_edges
"""Returns a graph with added reverse edges."""
import logging
from typing import Any, Dict, Union
import networkx as nx
__all__ = ["add_reverse_edges"]
[docs]
def add_reverse_edges(
graph: nx.MultiDiGraph,
*,
mapping: Union[Dict[Any, Any], None] = None,
) -> nx.MultiDiGraph:
"""Returns a graph with added reverse edges (with suffix '_r' by default).
Parameters
----------
graph : MultiDiGraph
Initial graph.
mapping: Dict[Any, Any]
Edge labels mapping for reverse edges that must be added.
Examples
--------
>>> from cfpq_data import *
>>> g = labeled_cycle_graph(2)
>>> list(g.edges(data=True))
[(0, 1, {'label': 'a'}), (1, 0, {'label': 'a'})]
>>> new_g = add_reverse_edges(g)
>>> list(new_g.edges(data=True))
[(0, 1, {'label': 'a'}), (0, 1, {'label': 'a_r'}), (1, 0, {'label': 'a_r'}), (1, 0, {'label': 'a'})]
Returns
-------
g : MultiDiGraph
A graph with added reverse edges.
"""
new_graph = nx.MultiDiGraph()
for node, node_labels in graph.nodes(data=True):
new_graph.add_node(node, **node_labels)
for u, v, edge_labels in graph.edges(data=True):
new_graph.add_edge(u, v, **edge_labels)
reverse_edge_labels = dict()
for key, value in edge_labels.items():
if not mapping:
reverse_edge_labels[key] = value + "_r"
elif value in mapping.keys():
reverse_edge_labels[key] = mapping[value]
if reverse_edge_labels != dict():
new_graph.add_edge(v, u, **reverse_edge_labels)
logging.info(f"Add reverse edges in {graph=} with {mapping=} to {new_graph=}")
return new_graph
