## Mercurial > repos > shellac > sam_consensus_v3

### view env/lib/python3.9/site-packages/networkx/algorithms/components/semiconnected.py @ 0:4f3585e2f14b draft default tip

Find changesets by keywords (author, files, the commit message), revision
number or hash, or revset expression.

"planemo upload commit 60cee0fc7c0cda8592644e1aad72851dec82c959"

author | shellac |
---|---|

date | Mon, 22 Mar 2021 18:12:50 +0000 |

parents | |

children |

line wrap: on

line source

"""Semiconnectedness.""" import networkx as nx from networkx.utils import not_implemented_for, pairwise __all__ = ["is_semiconnected"] @not_implemented_for("undirected") def is_semiconnected(G, topo_order=None): """Returns True if the graph is semiconnected, False otherwise. A graph is semiconnected if, and only if, for any pair of nodes, either one is reachable from the other, or they are mutually reachable. Parameters ---------- G : NetworkX graph A directed graph. topo_order: list or tuple, optional A topological order for G (if None, the function will compute one) Returns ------- semiconnected : bool True if the graph is semiconnected, False otherwise. Raises ------ NetworkXNotImplemented If the input graph is undirected. NetworkXPointlessConcept If the graph is empty. Examples -------- >>> G = nx.path_graph(4, create_using=nx.DiGraph()) >>> print(nx.is_semiconnected(G)) True >>> G = nx.DiGraph([(1, 2), (3, 2)]) >>> print(nx.is_semiconnected(G)) False See Also -------- is_strongly_connected is_weakly_connected is_connected is_biconnected """ if len(G) == 0: raise nx.NetworkXPointlessConcept( "Connectivity is undefined for the null graph." ) if not nx.is_weakly_connected(G): return False G = nx.condensation(G) if topo_order is None: topo_order = nx.topological_sort(G) return all(G.has_edge(u, v) for u, v in pairwise(topo_order))