Source code for cfpq_data.graphs.generators.labeled_two_cycles_graph
"""Returns a graph with two cycles connected by one node. With labeled edges."""
import logging
from typing import Union, Iterable, Any, Tuple
import networkx as nx
__all__ = ["labeled_two_cycles_graph"]
[docs]
def labeled_two_cycles_graph(
n: Union[int, Iterable[Any]],
m: Union[int, Iterable[Any]],
*,
common_node: Union[int, Any] = 0,
labels: Tuple[str, str] = ("a", "b"),
) -> nx.MultiDiGraph:
"""Returns a graph with two cycles connected by one node. With labeled edges.
Parameters
----------
n : Union[int, Iterable[Any]]
The number of nodes in the first cycle without a common node.
If n is an integer, nodes are from `range(n)`.
If n is a container of nodes, those nodes appear in the graph.
m : Union[int, Iterable[Any]]
The number of nodes in the second cycle without a common node.
If m is an integer, nodes are from `range(n)`.
If m is a container of nodes, those nodes appear in the graph.
common_node : Union[int, Any]
The node along which two cycles are connected.
labels: Tuple[str, str]
Labels that will be used to mark the edges of the graph.
Examples
--------
>>> from cfpq_data import *
>>> g = labeled_two_cycles_graph(42, 29)
>>> g.number_of_nodes()
72
>>> g.number_of_edges()
73
Returns
-------
g : MultiDiGraph
A graph with two cycles connected by one node.
"""
g1 = nx.path_graph(n=n, create_using=nx.MultiDiGraph)
if isinstance(n, int):
g1_number_of_nodes = g1.number_of_nodes()
g1_nodes = map(lambda x: x + 1, g1.nodes)
g1 = nx.path_graph(n=g1_nodes, create_using=nx.MultiDiGraph)
g2 = nx.path_graph(n=m, create_using=nx.MultiDiGraph)
if isinstance(m, int):
g1_number_of_nodes = g1.number_of_nodes()
g2_nodes = map(lambda x: x + g1_number_of_nodes + 1, g2.nodes)
g2 = nx.path_graph(n=g2_nodes, create_using=nx.MultiDiGraph)
for tmp in [g1, g2]:
first_node = list(tmp.nodes)[0]
last_node = list(tmp.nodes)[-1]
tmp.add_edge(common_node, first_node)
tmp.add_edge(last_node, common_node)
for edge in g1.edges:
g1.edges[edge]["label"] = labels[0]
for edge in g2.edges:
g2.edges[edge]["label"] = labels[1]
graph = nx.MultiDiGraph(nx.compose(g1, g2))
logging.info(
f"Create a {graph=} with two cycles connected by one node "
f"with {n=}, {m=}, {common_node=}, {labels=}"
)
return graph
