Warning
This documents an unmaintained version of NetworkX. Please upgrade to a maintained version and see the current NetworkX documentation.
biconnected_components¶

biconnected_components
(G)[source]¶ Return a generator of sets of nodes, one set for each biconnected component of the graph
Biconnected components are maximal subgraphs such that the removal of a node (and all edges incident on that node) will not disconnect the subgraph. Note that nodes may be part of more than one biconnected component. Those nodes are articulation points, or cut vertices. The removal of articulation points will increase the number of connected components of the graph.
Notice that by convention a dyad is considered a biconnected component.
Parameters: G : NetworkX Graph
An undirected graph.
Returns: nodes : generator
Generator of sets of nodes, one set for each biconnected component.
Raises: NetworkXNotImplemented :
If the input graph is not undirected.
See also
is_biconnected
,articulation_points
,biconnected_component_edges
,biconnected_component_subgraphs
Notes
The algorithm to find articulation points and biconnected components is implemented using a nonrecursive depthfirstsearch (DFS) that keeps track of the highest level that back edges reach in the DFS tree. A node \(n\) is an articulation point if, and only if, there exists a subtree rooted at \(n\) such that there is no back edge from any successor of \(n\) that links to a predecessor of \(n\) in the DFS tree. By keeping track of all the edges traversed by the DFS we can obtain the biconnected components because all edges of a bicomponent will be traversed consecutively between articulation points.
References
[R209] Hopcroft, J.; Tarjan, R. (1973). “Efficient algorithms for graph manipulation”. Communications of the ACM 16: 372–378. doi:10.1145/362248.362272 Examples
>>> G = nx.barbell_graph(4,2) >>> print(nx.is_biconnected(G)) False >>> components = nx.biconnected_components(G) >>> G.add_edge(2,8) >>> print(nx.is_biconnected(G)) True >>> components = nx.biconnected_components(G)