edge_bfs(G, source=None, orientation=None)
Yield the edges of G in a breadth-first-search order continuing until all edges are generated.
The goal of this function is to visit edges. It differs from the more familiar breadth-first-search of nodes, as provided by networkx.algorithms.traversal.breadth_first_search.bfs_edges
, in that it does not stop once every node has been visited. In a directed graph with edges [(0, 1), (1, 2), (2, 1)], the edge (2, 1) would not be visited if not for the functionality provided by this function.
The naming of this function is very similar to bfs_edges. The difference is that 'edge_bfs' yields edges even if they extend back to an already explored node while 'bfs_edges' yields the edges of the tree that results from a breadth-first-search (BFS) so no edges are reported if they extend to already explored nodes. That means 'edge_bfs' reports all edges while 'bfs_edges' only report those traversed by a node-based BFS. Yet another description is that 'bfs_edges' reports the edges traversed during BFS while 'edge_bfs' reports all edges in the order they are explored.
A directed/undirected graph/multigraph.
The node from which the traversal begins. If None, then a source is chosen arbitrarily and repeatedly until all edges from each node in the graph are searched.
For directed graphs and directed multigraphs, edge traversals need not respect the original orientation of the edges. When set to 'reverse' every edge is traversed in the reverse direction. When set to 'ignore', every edge is treated as undirected. When set to 'original', every edge is treated as directed. In all three cases, the yielded edge tuples add a last entry to indicate the direction in which that edge was traversed. If orientation is None, the yielded edge has no direction indicated. The direction is respected, but not reported.
A directed, breadth-first-search of edges in G, beginning at :None:None:`source`.
A directed edge indicating the path taken by the breadth-first-search. For graphs, :None:None:`edge` is of the form :None:None:`(u, v)` where u and :None:None:`v` are the tail and head of the edge as determined by the traversal. For multigraphs, :None:None:`edge` is of the form :None:None:`(u, v, key)`, where :None:None:`key` is the key of the edge. When the graph is directed, then u and :None:None:`v` are always in the order of the actual directed edge. If orientation is not None then the edge tuple is extended to include the direction of traversal ('forward' or 'reverse') on that edge.
>>> nodes = [0, 1, 2, 3]
... edges = [(0, 1), (1, 0), (1, 0), (2, 0), (2, 1), (3, 1)]
>>> list(nx.edge_bfs(nx.Graph(edges), nodes)) [(0, 1), (0, 2), (1, 2), (1, 3)]
>>> list(nx.edge_bfs(nx.DiGraph(edges), nodes)) [(0, 1), (1, 0), (2, 0), (2, 1), (3, 1)]
>>> list(nx.edge_bfs(nx.MultiGraph(edges), nodes)) [(0, 1, 0), (0, 1, 1), (0, 1, 2), (0, 2, 0), (1, 2, 0), (1, 3, 0)]
>>> list(nx.edge_bfs(nx.MultiDiGraph(edges), nodes)) [(0, 1, 0), (1, 0, 0), (1, 0, 1), (2, 0, 0), (2, 1, 0), (3, 1, 0)]
>>> list(nx.edge_bfs(nx.DiGraph(edges), nodes, orientation="ignore")) [(0, 1, 'forward'), (1, 0, 'reverse'), (2, 0, 'reverse'), (2, 1, 'reverse'), (3, 1, 'reverse')]
>>> list(nx.edge_bfs(nx.MultiDiGraph(edges), nodes, orientation="ignore")) [(0, 1, 0, 'forward'), (1, 0, 0, 'reverse'), (1, 0, 1, 'reverse'), (2, 0, 0, 'reverse'), (2, 1, 0, 'reverse'), (3, 1, 0, 'reverse')]See :
The following pages refer to to this document either explicitly or contain code examples using this.
networkx.algorithms.traversal.breadth_first_search.bfs_edges
networkx.algorithms.traversal.breadth_first_search.bfs_predecessors
networkx.algorithms.traversal.breadth_first_search.bfs_successors
networkx.algorithms.traversal.edgebfs.edge_bfs
networkx.algorithms.traversal.breadth_first_search.bfs_tree
Hover to see nodes names; edges to Self not shown, Caped at 50 nodes.
Using a canvas is more power efficient and can get hundred of nodes ; but does not allow hyperlinks; , arrows or text (beyond on hover)
SVG is more flexible but power hungry; and does not scale well to 50 + nodes.
All aboves nodes referred to, (or are referred from) current nodes; Edges from Self to other have been omitted (or all nodes would be connected to the central node "self" which is not useful). Nodes are colored by the library they belong to, and scaled with the number of references pointing them