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Diffstat (limited to '.venv/lib/python3.12/site-packages/networkx/algorithms/centrality/degree_alg.py')
-rw-r--r-- | .venv/lib/python3.12/site-packages/networkx/algorithms/centrality/degree_alg.py | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/networkx/algorithms/centrality/degree_alg.py b/.venv/lib/python3.12/site-packages/networkx/algorithms/centrality/degree_alg.py new file mode 100644 index 00000000..b3c1e321 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/networkx/algorithms/centrality/degree_alg.py @@ -0,0 +1,150 @@ +"""Degree centrality measures.""" + +import networkx as nx +from networkx.utils.decorators import not_implemented_for + +__all__ = ["degree_centrality", "in_degree_centrality", "out_degree_centrality"] + + +@nx._dispatchable +def degree_centrality(G): + """Compute the degree centrality for nodes. + + The degree centrality for a node v is the fraction of nodes it + is connected to. + + Parameters + ---------- + G : graph + A networkx graph + + Returns + ------- + nodes : dictionary + Dictionary of nodes with degree centrality as the value. + + Examples + -------- + >>> G = nx.Graph([(0, 1), (0, 2), (0, 3), (1, 2), (1, 3)]) + >>> nx.degree_centrality(G) + {0: 1.0, 1: 1.0, 2: 0.6666666666666666, 3: 0.6666666666666666} + + See Also + -------- + betweenness_centrality, load_centrality, eigenvector_centrality + + Notes + ----- + The degree centrality values are normalized by dividing by the maximum + possible degree in a simple graph n-1 where n is the number of nodes in G. + + For multigraphs or graphs with self loops the maximum degree might + be higher than n-1 and values of degree centrality greater than 1 + are possible. + """ + if len(G) <= 1: + return {n: 1 for n in G} + + s = 1.0 / (len(G) - 1.0) + centrality = {n: d * s for n, d in G.degree()} + return centrality + + +@not_implemented_for("undirected") +@nx._dispatchable +def in_degree_centrality(G): + """Compute the in-degree centrality for nodes. + + The in-degree centrality for a node v is the fraction of nodes its + incoming edges are connected to. + + Parameters + ---------- + G : graph + A NetworkX graph + + Returns + ------- + nodes : dictionary + Dictionary of nodes with in-degree centrality as values. + + Raises + ------ + NetworkXNotImplemented + If G is undirected. + + Examples + -------- + >>> G = nx.DiGraph([(0, 1), (0, 2), (0, 3), (1, 2), (1, 3)]) + >>> nx.in_degree_centrality(G) + {0: 0.0, 1: 0.3333333333333333, 2: 0.6666666666666666, 3: 0.6666666666666666} + + See Also + -------- + degree_centrality, out_degree_centrality + + Notes + ----- + The degree centrality values are normalized by dividing by the maximum + possible degree in a simple graph n-1 where n is the number of nodes in G. + + For multigraphs or graphs with self loops the maximum degree might + be higher than n-1 and values of degree centrality greater than 1 + are possible. + """ + if len(G) <= 1: + return {n: 1 for n in G} + + s = 1.0 / (len(G) - 1.0) + centrality = {n: d * s for n, d in G.in_degree()} + return centrality + + +@not_implemented_for("undirected") +@nx._dispatchable +def out_degree_centrality(G): + """Compute the out-degree centrality for nodes. + + The out-degree centrality for a node v is the fraction of nodes its + outgoing edges are connected to. + + Parameters + ---------- + G : graph + A NetworkX graph + + Returns + ------- + nodes : dictionary + Dictionary of nodes with out-degree centrality as values. + + Raises + ------ + NetworkXNotImplemented + If G is undirected. + + Examples + -------- + >>> G = nx.DiGraph([(0, 1), (0, 2), (0, 3), (1, 2), (1, 3)]) + >>> nx.out_degree_centrality(G) + {0: 1.0, 1: 0.6666666666666666, 2: 0.0, 3: 0.0} + + See Also + -------- + degree_centrality, in_degree_centrality + + Notes + ----- + The degree centrality values are normalized by dividing by the maximum + possible degree in a simple graph n-1 where n is the number of nodes in G. + + For multigraphs or graphs with self loops the maximum degree might + be higher than n-1 and values of degree centrality greater than 1 + are possible. + """ + if len(G) <= 1: + return {n: 1 for n in G} + + s = 1.0 / (len(G) - 1.0) + centrality = {n: d * s for n, d in G.out_degree()} + return centrality |