Changing the color of one particular node into different colors

function pt = plot_topology_1(filename)

     newfilename = [filename, '.network'];
     fileID = fopen(newfilename);

     if fileID == -1
         error('Author:Function:OpenFile', 'Cannot open file: %s', newfilename);
     end

     C = textscan(fileID,'%c %d %d %f32 %f32 %f32 %f32 \n','Delimiter',',','HeaderLines',1);
     fclose(fileID);
     no_of_edges = length(C{1})
     final = no_of_edges;

     a = C{2};
     b = C{3};

     edgewidth = C{5};
     weights = randi([1 40],1, final);
      
     G = graph(a,b,weights)
     aa=incidence(G)
     sup=supply_nodes(aa)    %function of supply nodes
     dem = demand_nodes(aa)  %function of demand nodes
     
     col= [0.3 8 12 5];
        d=length(col)
     i=0;
   for i=1:d
         if i==1
             c='r';
         elseif i==2
             c='g';
         elseif i==3
             c='b';
         else i==4
             c='m';
         end
    
      p = plot(G)
     highlight(p,sup, c )  % supply node color
    highlight(p,dem,'NodeColor','g')    %demand node color
  end
end

there is only one supply node in this network and is indicated by red color. I want change the supply node color step by step in four diffrerent colors following the some given values. I made an array of 1*4 for four different color. But it shows that Matlab doesn't support the function. Please help me to figure it out.

Answer 1

[Steven Lord]

What is the full and exact text of the error message you receive when you run that code? Include all the text displayed in red, exactly as it's shown in the Command Window. Don't paraphrase or summarize.

You also haven't shown us the functions supply_nodes and demand_nodes.

Finally, you probably don't want to plot the graph multiple times, once per element in your col vector. plot it once then highlight it multiple times (or highlight it with a vector of node IDs to change all those nodes at once.)

[Steven Lord]

That code works as I would expect it to work. I'm not certain what you're trying to do when you say "I want to change the supply node color with given numbers of vector using Colorbar." Do you mean you have a colorbar in your figure and you want to specify, say, 17 and change the color of the supply node to the 17th color in the colorbar? If so, set the NodeCData property to a vector of indices into the colormap then set the NodeColor property to 'flat'.

[Kashfia Mahin]

I tried with NodeCData. I got the result.

t = [1 1 1 1];
h = [2 3 4 5];
g = graph(t,h)
p = plot(g)

g.Nodes.value = [0.3; 0.564; 12; 1; 0.005];
g.Nodes.NodeColors = g.Nodes.value;

p.NodeCData = g.Nodes.NodeColors;

q= plot(g,'NodeCData',g.Nodes.NodeColors);
colorbar

Is it possible to change the color of a particular node into 3 or 4 different colors with a colorbar??

[Steven Lord]

Change the appropriate elements of the NodeCData property of the GraphPlot object q. Note that as you created it the NodeCData for all elements but 3 are at or below 1, in the dark blue section of your colorbar, while node 3's NodeCData is 12, in the topmost yellow section of the colorbar. This matches the colors you see in the figure.

q.NodeCData(5) = 8; % should make it green

[Kashfia Mahin]

Thank you so much. It works perfectly

[Kashfia Mahin]

Error using digraph/subsasgn (line 51)

To assign to or create a variable in a table, the number of rows must match the height of the table.

Error in plot_topology_mahin (line 32)

G.Nodes.value = randi([1 12],1,N); %Nodes value of all the nodes available in the network

Now I read the no of nodes from a network. i used randi function to generate Node value for the Node Colors following the number of nodes. There is a error showing which I don't figure it out how to solve.

[Steven Lord]

This is close to a new issue, but it's easy to solve so I'll just respond here. If you encounter more problems that aren't directly related to the node coloring you may want to post a new question (perhaps linking back here for background material.)

N = 12;
t = table((1:N).')
r = randi([1 12], 1, N)
s = randi([1 12], N, 1)

What is the height of the table t?

What is the number of rows in r?

What is the number of rows in s?

You could use s to add a new variable to t, but you cannot use r to add a new variable to t. s and r have the same number of elements but not the same number of rows and that makes a big difference.

t.newvar1 = s % Works
t.newvar2 = r % Does not work