networkx.generators.expanders.chordal_cycle_graph¶
-
chordal_cycle_graph
(p, create_using=None)[source]¶ Return the chordal cycle graph on
p
nodes.The returned graph is a cycle graph on
p
nodes with chords joining each vertexx
to its inverse modulop
. This graph is a (mildly explicit) 3-regular expander [1].p
must be a prime number.Parameters: - p (a prime number) – The number of vertices in the graph. This also indicates where the chordal edges in the cycle will be created.
- create_using (graph-like) – A graph-like object that receives the constructed edges. If None,
then a
MultiGraph
instance is used.
Returns: G – The constructed undirected multigraph.
Return type: graph
Raises: NetworkXError
– If the graph provided increate_using
is directed or not a multigraph.References
[1] Theorem 4.4.2 in A. Lubotzky. “Discrete groups, expanding graphs and invariant measures”, volume 125 of Progress in Mathematics. Birkhäuser Verlag, Basel, 1994.