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predecessors

Node predecessors

Syntax

preIDs = predecessors(G,nodeID)

Description

example

preIDs = predecessors(G,nodeID) returns the predecessor nodes of the node in directed graph G specified by nodeID. The predecessor nodes form directed edges with preIDs as the source nodes, and nodeID as the target node.

Examples

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Create and plot a directed graph and determine the predecessor nodes of node 'e'.

s = [1 1 1 2 2 3 3 7 8];
t = [2 3 4 5 6 7 8 5 5];
names = {'a' 'b' 'c' 'd' 'e' 'f' 'g' 'h'};
G = digraph(s,t,[],names);
plot(G)

preIDs = predecessors(G,'e')
preIDs = 3x1 cell array
    {'b'}
    {'g'}
    {'h'}

Input Arguments

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

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

Node identifier, specified as one of the values in this table.

ValueExample
Scalar node index1
Character vector node name'A'
String scalar node name"A"

Example: preIDs = predecessors(G,3) finds the predecessor nodes of node 3.

Output Arguments

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Predecessor node IDs, returned as a node indices or node names.

  • If nodeID is a numeric node index, then preIDs contains numeric node indices.

  • If nodeID is a node name, then preIDs contains node names.

Tips

  • For multigraphs with multiple edges between the same two nodes, the output of inedges can be longer than that of predecessors, since there can be multiple incoming edges from some of the predecessors.

Introduced in R2015b