networkx.eulerian_circuit

eulerian_circuit(G, source=None)

Return the edges of an Eulerian circuit in G.

An Eulerian circuit is a path that crosses every edge in G exactly once and finishes at the starting node.

Parameters:

G : NetworkX graph

source : node, optional

Starting node for circuit.

Returns:

edges : generator

A generator that produces edges in the Eulerian circuit.

Notes

Uses Fleury’s algorithm [R51],[R52]_

References

[R51]

(1, 2) Fleury, “Deux problemes de geometrie de situation”, Journal de mathematiques elementaires (1883), 257-261.

[R52]

http://en.wikipedia.org/wiki/Eulerian_path

Examples

>>> G=nx.complete_graph(3)
>>> list( eulerian_circuit(G) )
[(0, 1), (1, 2), (2, 0)]
>>> list( eulerian_circuit(G,source=1) ) 
[(1, 0), (0, 2), (2, 1)]
>>> [u for u,v in eulerian_circuit(G)]  # nodes in circuit
[0, 1, 2]