MATLAB: How to add edges to a graph plot using GraphPlot handle

figuregraphgraph theorygraphplotplot

Is it possible to update a graphplot figure to add edges or nodes, using GraphPlot handle? What is the most efficient way to do this instead of calling

plot(graph)

function repeatedly.

Best Answer

There is currently no way to do this, the edges and nodes must be modified on the graph or digraph, and then this can be passed into the plot function.

Could you say some more about why you would prefer to modify them directly on the GraphPlot object?

Related Solutions

MATLAB: Delete and add new edges in a graph

A graph object is undirected. A digraph object is directed.

Construct your network graph using digraph instead of graph on the fourth line of your code.

By the way, the addedge function has two capabilities you might find useful.

The s (source) and t (target) inputs can be vectors to add multiple edges at once.
If the source and/or target inputs reference nodes that don't yet exist, addedge adds them.

So you could do this with something like:

% Make a digraph and plot it for later reference
G = digraph(triu(ones(3)));
figure;
plot(G)
% How many nodes does G have?
N = numnodes(G);
% Add 2 new nodes
newnodes = [N+1 N+2];
% Add the edges between 1 and N+1, N+1 and N+2, and N+2 and 2
%

% I'm doing this in a copy of G, rather than G itself so you can go back
% and compare G and G2. But you can modify G itself if you want.
%
% Because of the way I created G, it's a weighted digraph, so I need
% to give the new edges weights. I chose to weight them all pi.
% Scalar expansion lets me specify a scalar weight to be used for each new edge.
G2 = addedge(G, [1 newnodes], [newnodes 2], pi);
% Eliminate the edge from 1 to 2
G2 = rmedge(G2, 1, 2);
% Plot the new digraph
figure;
plot(G2)

MATLAB: Modify Nodes and Edges of GraphPlot

I'm afraid that's not possible with GraphPlot.

For performance, you could use scatter to plot all the nodes, and plot to plot all edges connecting these nodes as straight lines, this would be much more efficient - of course it loses some of the additional features, like placement of the nodes in an automatic graph plot.

Or maybe you could safe the plot of each timestep ahead of time and then play the animation based on this precomputed set?

In GraphPlot, in terms of node placement, if you don't already know the coordinates at which the nodes should be placed in each timestep, you could try feeding the coordinates of the last timestep to the 'XStart', 'YStart' options for the 'force' layout, which would make the nodes in the next step be in a more similar place to the previous one. Changing 'Iterations' to a smaller number could also be helpful there.

Best Answer

Related Solutions

MATLAB: Delete and add new edges in a graph

MATLAB: Modify Nodes and Edges of GraphPlot

Related Question