Warning
This documents an unmaintained version of NetworkX. Please upgrade to a maintained version and see the current NetworkX documentation.
topological_sort¶
- topological_sort(G, nbunch=None, reverse=False)[source]¶
Return a list of nodes in topological sort order.
A topological sort is a nonunique permutation of the nodes such that an edge from u to v implies that u appears before v in the topological sort order.
Parameters : G : NetworkX digraph
A directed graph
nbunch : container of nodes (optional)
Explore graph in specified order given in nbunch
reverse : bool, optional
Return postorder instead of preorder if True. Reverse mode is a bit more efficient.
Raises : NetworkXError
Topological sort is defined for directed graphs only. If the graph G is undirected, a NetworkXError is raised.
NetworkXUnfeasible
If G is not a directed acyclic graph (DAG) no topological sort exists and a NetworkXUnfeasible exception is raised.
See also
Notes
This algorithm is based on a description and proof in The Algorithm Design Manual [R234] .
References
[R234] (1, 2) Skiena, S. S. The Algorithm Design Manual (Springer-Verlag, 1998). http://www.amazon.com/exec/obidos/ASIN/0387948600/ref=ase_thealgorithmrepo/