dag_longest_path¶

dag_longest_path(G, weight='weight', default_weight=1, topo_order=None)[source]¶

Returns the longest path in a directed acyclic graph (DAG).

If G has edges with weight attribute the edge data are used as weight values.

Parameters

GNetworkX DiGraph: A directed acyclic graph (DAG)
weightstr, optional: Edge data key to use for weight
default_weightint, optional: The weight of edges that do not have a weight attribute
topo_order: list or tuple, optional: A topological order for G (if None, the function will compute one)

Returns

list: Longest path

Raises

NetworkXNotImplemented: If G is not directed

See also

dag_longest_path_length

Examples

>>> DG = nx.DiGraph([(0, 1, {'cost':1}), (1, 2, {'cost':1}), (0, 2, {'cost':42})])
>>> list(nx.all_simple_paths(DG, 0, 2))
[[0, 1, 2], [0, 2]]
>>> nx.dag_longest_path(DG)
[0, 1, 2]
>>> nx.dag_longest_path(DG, weight="cost")
[0, 2]