degree

Degree of graph nodes

Syntax

D = degree(G)

D = degree(G,nodeIDs)

Description

D = degree(G) returns the degree of each node in graph G. The degree is the number of edges connected to each node.

D = degree(G,nodeIDs) returns the degree of the nodes specified by nodeIDs.

Examples

Degree of All Graph Nodes

Create and plot a graph, and then use degree to find the degree of each node in the graph.

s = [1 1 1 4 4 6 6 6];
t = [2 3 4 5 6 7 8 9];
G = graph(s,t);
plot(G)

deg = degree(G)

deg = 9×1

     3
     1
     1
     3
     1
     4
     1
     1
     1

deg(j) indicates the degree of node j.

Degree of Subset of Graph Nodes

Create and plot a graph, and then find the degree of the first, third, and fifth nodes.

s = {'a' 'a' 'a' 'd' 'd' 'f' 'f' 'f'};
t = {'b' 'c' 'd' 'e' 'f' 'g' 'h' 'i'};
G = graph(s,t);
plot(G)

nodeIDs = {'a' 'c' 'e'}';
deg = degree(G,nodeIDs)

deg = 3×1

     3
     1
     1

deg(j) indicates the degree of node nodeIDs(j).

Input Arguments

G — Input graph

graph object

Input graph, specified as a graph object. Use graph to create an undirected graph object.

Example: G = graph(1,2)

nodeIDs — Node identifiers

scalar | vector | matrix | character vector | cell array of character vectors

Node identifiers, specified as a scalar node index, a vector or matrix of numeric node indices, a character vector node name, or a cell array of character vectors containing node names. You can refer to the nodes either by their numeric node index or by their node names.

Example: D = degree(G,[3 4])

Example: D = degree(G,{'LAX','ALB'})

Output Arguments

D — Degree of nodes

array

Degree of nodes, returned as a numeric array. D is a column vector unless you specify nodeIDs, in which case D has the same size as nodeIDs.

A node that is connected to itself by an edge (a self-loop) is listed as its own neighbor only once, but the self-loop adds 2 to the total degree of the node.