indegree

In-degree of nodes

Syntax

D = indegree(G)

D = indegree(G,nodeIDs)

Description

D = indegree(G) returns a column vector containing the in-degree of each node in G.

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

Examples

In-Degree of All Graph Nodes

Create and plot a directed graph, and then compute the in-degree of every node in the graph. The in-degree of a node is equal to the number of edges with that node as the target.

s = [1 3 2 2 4 5 1 2];
t = [2 2 4 5 6 6 6 6];
G = digraph(s,t);
plot(G)

indeg = indegree(G)

indeg = 6×1

     0
     2
     0
     1
     1
     4

indeg(j) indicates the in-degree of node j.

In-Degree of Subset of Graph Nodes

Create and plot a directed graph with named nodes. Then compute the number of edges that have the 'a', 'b', and 'f' nodes as their target.

s = {'a' 'c' 'b' 'b' 'd' 'e' 'a' 'b'};
t = {'b' 'b' 'd' 'e' 'f' 'f' 'f' 'f'};
G = digraph(s,t);
plot(G)

nodeID = {'a' 'b' 'f'}';
indeg = indegree(G,nodeID)

indeg = 3×1

     0
     2
     4

indeg(j) indicates the in-degree of node nodeID(j).

Input Arguments

G — Input graph

digraph object

Input graph, specified as a digraph object. Use digraph to create a directed graph object.

Example: G = digraph([1 2],[2 3])

nodeIDs — Node identifiers

node indices | node names

Node identifiers, specified as one or more node indices or node names.

This table shows the different ways to refer to one or more nodes either by their numeric node indices or by their node names.

Form	Single Node	Multiple Nodes
Node index	Scalar Example: 1	Vector Example: [1 2 3]
Node name	Character vector Example: 'A'	Cell array of character vectors Example: {'A' 'B' 'C'}
	String scalar Example: "A"	String array Example: ["A" "B" "C"]

Example: indegree(G,1)

Example: indegree(G,["A" "B" "C"])

Output Arguments

D — In-degree of nodes

array

In-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.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• The node identifiers nodeIDs must be one or more node indices of the input graph G. Node names are not supported.

Thread-Based Environment
Run code in the background using MATLAB® backgroundPool or accelerate code with Parallel Computing Toolbox™ ThreadPool.

Version History

Introduced in R2015b