is_weakly_connected#

is_weakly_connected(G)[source]#

Test directed graph for weak connectivity.

A directed graph is weakly connected if and only if the graph is connected when the direction of the edge between nodes is ignored.

Note that if a graph is strongly connected (i.e. the graph is connected even when we account for directionality), it is by definition weakly connected as well.

Parameters:

GNetworkX Graph: A directed graph.

Returns:

connectedbool: True if the graph is weakly connected, False otherwise.

Raises:

NetworkXNotImplemented: If G is undirected.

See also

is_strongly_connected
is_semiconnected
is_connected
is_biconnected
weakly_connected_components

Notes

For directed graphs only.

Examples

>>> G = nx.DiGraph([(0, 1), (2, 1)])
>>> G.add_node(3)
>>> nx.is_weakly_connected(G)  # node 3 is not connected to the graph
False
>>> G.add_edge(2, 3)
>>> nx.is_weakly_connected(G)
True

Additional backends implement this function

cugraph : GPU-accelerated backend.

graphblas : OpenMP-enabled sparse linear algebra backend.