# networkx.algorithms.shortest_paths.weighted.single_source_bellman_ford_path_length¶

single_source_bellman_ford_path_length(G, source, weight='weight')[source]

Compute the shortest path length between source and all other reachable nodes for a weighted graph.

Parameters
• G (NetworkX graph)

• source (node label) – Starting node for path

• weight (string, optional (default=’weight’)) – Edge data key corresponding to the edge weight.

Returns

length – (target, shortest path length) iterator

Return type

iterator

Raises

NodeNotFound – If source is not in G.

Examples

>>> G = nx.path_graph(5)
>>> length = dict(nx.single_source_bellman_ford_path_length(G, 0))
>>> length[4]
4
>>> for node in [0, 1, 2, 3, 4]:
...     print(f"{node}: {length[node]}")
0: 0
1: 1
2: 2
3: 3
4: 4


Notes

Edge weight attributes must be numerical. Distances are calculated as sums of weighted edges traversed.