gplot

Plot nodes and edges in adjacency matrix

Syntax

gplot(A,XYCoords)

gplot(A,XYCoords,LineSpec)

[x,y] = gplot(A,XYCoords)

Description

gplot(A,XYCoords) plots a graph of the nodes and edges defined in the adjacency matrix A at the coordinates specified in XYCoords. The adjacency matrix A is an n-by-n matrix, where n is the number of nodes. XYCoords is an n-by-2 matrix specifying xy-coordinates for each node.

gplot(A,XYCoords,LineSpec) additionally uses LineSpec to specify the line type, marker symbol, and color to use in the plot. For example, gplot(A,XY,'r-*') uses red lines for edges and red asterisks for nodes.

[x,y] = gplot(A,XYCoords) returns the NaN-delimited vectors x and y without generating a plot. Use x and y to generate a plot at a later time using plot(x,y).

Examples

Plot Graph of Nodes Using Asterisks

Plot half of the carbon-60 molecule, placing asterisks at each node.

k = 1:30;
[B,XY] = bucky;
gplot(B(k,k),XY(k,[1 2]),'-*')
axis square

Input Arguments

A — Adjacency matrix

matrix

Adjacency matrix, specified as a matrix. A describes the connections between the nodes in the graph by the location of nonzero values. If node i and node j are connected, then A(i,j) or A(j,i) is nonzero; otherwise, A(i,j) and A(j,i) are zero.

Example: A = ones(5) is the adjacency matrix of a graph with five nodes where each node is connected to all the others.

Example: A = [0 1 1 1; 1 0 0 0; 1 0 0 0; 1 0 0 0] is the adjacency matrix of a graph with four nodes where one node connects to the other three.

Data Types: single | double

XYCoords — xy-coordinates of nodes

N-by-2 matrix

xy-coordinates of nodes, specified as an N-by-2 matrix. Each row in XYCoords defines the coordinates for one node in the graph, so XYCoords(i,:) = [x(i) y(i)] gives the coordinates for node i.

Example: XYCoords = [1 2; 3 4] plots one node at (1,2) and a second node at (3,4).

LineSpec — Line style, marker, and color

string scalar | character vector

Line style, marker, and color, specified as a string scalar or character vector containing symbols. The symbols can appear in any order. You do not need to specify all three characteristics (line style, marker, and color). For example, if you omit the line style and specify the marker, then the plot shows only the marker and no line.

Example: "--or" is a red dashed line with circle markers.

Line Style	Description	Resulting Line
"-"	Solid line
"--"	Dashed line
":"	Dotted line
"-."	Dash-dotted line

Marker	Description	Resulting Marker
"o"	Circle
"+"	Plus sign
"*"	Asterisk
"."	Point
"x"	Cross
"_"	Horizontal line
"|"	Vertical line
"square"	Square
"diamond"	Diamond
"^"	Upward-pointing triangle
"v"	Downward-pointing triangle
">"	Right-pointing triangle
"<"	Left-pointing triangle
"pentagram"	Pentagram
"hexagram"	Hexagram

Color Name	Short Name	RGB Triplet	Appearance
"red"	"r"	[1 0 0]
"green"	"g"	[0 1 0]
"blue"	"b"	[0 0 1]
"cyan"	"c"	[0 1 1]
"magenta"	"m"	[1 0 1]
"yellow"	"y"	[1 1 0]
"black"	"k"	[0 0 0]
"white"	"w"	[1 1 1]

Output Arguments

x, y — Node coordinates

vectors

Node coordinates, returned as vectors. x and y contain the same information as XYCoords, but in a different format that is suitable for plotting with the command plot(x,y). The line segments defined in x and y are separated with NaN values.

Tips

• Use graph and digraph objects to work with graph and network algorithms. You can visualize the networks with plot.

Version History

Introduced before R2006a