ó |£*^c@sLdZddlZdjddgƒZddgZd„Zdd „ZdS( s Eulerian circuits and graphs. iÿÿÿÿNs s&Nima Mohammadi (nima.irt[AT]gmail.com)sAric Hagberg t is_eulerianteulerian_circuitcCs£|jƒr[x6|jƒD](}|j|ƒ|j|ƒkrtSqWtj|ƒsŸtSnDx.|jƒD] \}}|ddkrhtSqhWtj|ƒsŸtSt S(sReturn True if G is an Eulerian graph, False otherwise. An Eulerian graph is a graph with an Eulerian circuit. Parameters ---------- G : graph A NetworkX Graph Examples -------- >>> nx.is_eulerian(nx.DiGraph({0:[3], 1:[2], 2:[3], 3:[0, 1]})) True >>> nx.is_eulerian(nx.complete_graph(5)) True >>> nx.is_eulerian(nx.petersen_graph()) False Notes ----- This implementation requires the graph to be connected (or strongly connected for directed graphs). ii( t is_directedt nodes_itert in_degreet out_degreetFalsetnxtis_strongly_connectedt degree_itert is_connectedtTrue(tGtntvtd((sm/home/gitlab-runner/builds/8480fa44/0/bergerc/fluidmanager-web/art-framework/bin/networkx/algorithms/euler.pyRs c csJddlm}t|ƒs.tjdƒ‚n|j|ƒ}|dkr^t|jƒƒ}n|}|j ƒr‘|j }|j }|dƒ}n|j }|j }|dƒ}|g}d} x…|rE|d} || ƒdkr| dk rý| | fVn| } |jƒqÁt|| ƒƒ} |j|| ƒƒ|j| ŒqÁWdS(s³Return 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 or DiGraph A directed or undirected graph source : node, optional Starting node for circuit. Returns ------- edges : generator A generator that produces edges in the Eulerian circuit. Raises ------ NetworkXError If the graph is not Eulerian. See Also -------- is_eulerian Notes ----- Linear time algorithm, adapted from [1]_. General information about Euler tours [2]_. References ---------- .. [1] J. Edmonds, E. L. Johnson. Matching, Euler tours and the Chinese postman. Mathematical programming, Volume 5, Issue 1 (1973), 111-114. .. [2] http://en.wikipedia.org/wiki/Eulerian_path Examples -------- >>> G=nx.complete_graph(3) >>> list(nx.eulerian_circuit(G)) [(0, 2), (2, 1), (1, 0)] >>> list(nx.eulerian_circuit(G,source=1)) [(1, 2), (2, 0), (0, 1)] >>> [u for u,v in nx.eulerian_circuit(G)] # nodes in circuit [0, 2, 1] iÿÿÿÿ(t itemgettersG is not Eulerian.iiN(toperatorRRRt NetworkXErrort __class__tNonetnextRRRt in_edges_itertdegreet edges_itertpoptappendt remove_edge( R tsourceRtgRRtedgest get_vertext vertex_stackt last_vertextcurrent_vertext random_edge((sm/home/gitlab-runner/builds/8480fa44/0/bergerc/fluidmanager-web/art-framework/bin/networkx/algorithms/euler.pyR=s41             ( t__doc__tnetworkxRtjoint __author__t__all__RRR(((sm/home/gitlab-runner/builds/8480fa44/0/bergerc/fluidmanager-web/art-framework/bin/networkx/algorithms/euler.pyts      +