How to fix this code? It doesnt give me an edge from 1 to 2! what is the problem in my code?

p = [3,2,1];
for i = 1:length(p)
  last_element = p(end);
  G = graph();
  H = addnode(G,last_element);
  p(end) = [];  % REMOVING THE LAST ELEMENT ONCE ADDED TO THE GRAPH so in 2nd iteration p = [3,2]
  disp(p);
  if(isempty(p))
    break;
  else
    disp(p(end));
    V = addedge(G,last_element,p(end));
  end
  plot(V);
end

Answer 1

[Walter Roberson]

I do not see any "hold" command, so the plot(V) is going to overwrite the plotted graph in each iteration.

You are deliberately creating a new graph() in each iteration of i, so it seems that you do not want to create one graph that has all of the edges together, only one edge at a time, but you are not displaying the individual graphs into different figures or subplots...

[Aswin Sandirakumaran]

Yea. SO how to fix it? so that in each iteration we can just add those in the plots and to obtain the final one containing all iteration? because in this case it just outputs my final iteration, it overwrites the on done previously. How to fix it? Can you help me?

Answer 2

[Steven Lord]

You want a graph with three nodes and two edges, those edges being (3, 2) and (2, 1)? You can do this with one call to graph.

p = [3 2 1];
sources = p(1:end-1)
targets = p(2:end)
g = graph(sources, targets)
plot(g)

You don't necessarily need to create the intermediate arrays sources and targets, I just did it so you can see what they contain.

p = [3 2 1];
g = graph(p(1:end-1), p(2:end))
plot(g)