networkx.generators.expanders.chordal_cycle_graph¶
-
chordal_cycle_graph
(p, create_using=None)[source]¶ Returns 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 (NetworkX graph constructor, optional (default=nx.Graph)) – Graph type to create. If graph instance, then cleared before populated.
- Returns
G – The constructed undirected multigraph.
- Return type
graph
- Raises
NetworkXError – If
create_using
indicates 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.