networkx.algorithms.dag.dag_longest_path_length

dag_longest_path_length(G, weight='weight', default_weight=1)[source]

Returns the longest path length in a DAG

Parameters
GNetworkX DiGraph

A directed acyclic graph (DAG)

weightstring, optional

Edge data key to use for weight

default_weightint, optional

The weight of edges that do not have a weight attribute

Returns
int

Longest path length

Raises
NetworkXNotImplemented

If G is not directed

See also

dag_longest_path

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_length(DG)
2
>>> nx.dag_longest_path_length(DG, weight="cost")
42