is_tree(G)
A tree is a connected graph with no undirected cycles.
For directed graphs, G is a tree if the underlying graph is a tree. The underlying graph is obtained by treating each directed edge as a single undirected edge in a multigraph.
In another convention, a directed tree is known as a polytree and then tree corresponds to an arborescence.
The graph to test.
If G is empty.
Returns True if G is a tree.
>>> G = nx.Graph()
... G.add_edges_from([(1, 2), (1, 3), (2, 4), (2, 5)])
... nx.is_tree(G) # n-1 edges True
>>> G.add_edge(3, 4)See :
... nx.is_tree(G) # n edges False
The following pages refer to to this document either explicitly or contain code examples using this.
networkx.algorithms.tree.recognition.is_tree
networkx.algorithms.tree.recognition.is_arborescence
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