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# How to use non-unique node names in a digraph?

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Monika Jaskolka on 1 Aug 2020
Answered: Christine Tobler on 3 Aug 2020
I am trying to plot a Simulink model as a graph. I am using the digraph function, but I am running into issues because Simulink elements can have non-unique names. For example, a model can have any amount of subsystems named "Subsystem", so long as they are at different hierarchical levels. The same goes for Inports named "In1", Outports named "Out1", etc. And given that these are the default names for these elements, there typically are many elements with the same names.
A simple example of what I want to acheive is shown in the image. However, I receive an error saying node names must be unique. Is there a better way of plotting graphs with non-unique names displayed? I don't want to append suffixes to make the labels unique, because that would make the plot inaccurate. s = [1 2 3];
t = [2 3 3];
w = ones(1, length(t));
n = {'Block Diagram', 'Subsystem', 'Subsystem'};
G = digraph(s, t, w, n, 'omitselfloops');
h = plot(G); ##### 0 CommentsShowHide -1 older comments

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### Accepted Answer

Christine Tobler on 3 Aug 2020
Instead of setting these inputs as node names, add them as a separate variable in the nodes table. Then, pass them to the plotting function as node labels:
G = digraph(s, t, w, [], 'omitselfloops');
G.Nodes.Label = n;
plot(G, 'NodeLabel', G.Nodes.Label);
The node names of a graph have to be unique because they can be used to specify a node as input to some functions (for example shortestpath). But this is not the case for the labels in the plot of a graph.
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