While running simulation, plot each curve with a different color

Hi all, I saw many thread on the same question but I guess I don't understand how it works. I want to get different possibilities for the phi matrix so I'm running simul and want a plot with all the curves with a different color. I don't know if the problem come from where I put the plot and hold on but would really appreciate some help ! This is a MWE.

{

nb=[];
total=[];
con=[];
nbcon=[];
simul=[];

 hold all 
 for simul=1:5
    phi=zeros(4,4);
    for nbIter=1:30
        Nel = numel(phi);
        Rindices = randperm(Nel);
        N10 = floor(Nel/10);
        phi(Rindices(1:N10)) = 1
        nbcon=sum(sum(phi))  

 nb=sum(sum(phi))*rand(1);
 con=[con; nb, nbcon];

    end
    plot(con(:,2),con(:,1),'color', rand(1,3))
end

 hold off

Answer 1

[Geoff Hayes]

The problem is that the code is plotting all the data at each iteration, including that which was plotted at previous iterations. So all points are being overwritten with the new random colour.

Just reset con to the empty matrix on each iteration of the outer for loop, that way the code doesn't hang on to the legacy data from previous iterations

for simul=1:5
    phi=zeros(4,4);
    con = [];       % new line of code to add

      % etc.

Try the above and see what happens!

[hibou]

Thanks for your answer. however, reset in "con" at each outer loop does do the trick to change the color but I get only one curve. When I'd like to get all the curve from each simul run to all be on the same plot and each simul run with a different color. Does it make sense? Thanks again for your help!

[Geoff Hayes]

Just create a figure and add hold on after it to retain the current graph when adding new graphs. Replace the

 hold all

with

 figure;
 hold on;

[Joseph Cheng]

Perhaps use a colormap to get the color to get some distinct colors to plot.

 Linecolor = hsv(numberoflines);

in the held plot

 plot(con(iteration,2),con(iteration,1),'color', Linecolor(iteration,:))

Answer 2

[hibou]

Geoff and Joseph, thanks for your help ! I really couldn't get where and when use the hold on command. The answer by Geoff Hayes pointed me that I had to delete the con matrix at the outer loop and Joseph Cheng helped me set up the plot colors. And here is a simple way for different color curve:

clc 
close all
clear all
nb=[];
total=[];
con=[];
nbcon=[];
simul=[];
for simul=1:5
  phi=zeros(4,4); 
  for nbIter=1:30
      Nel = numel(phi);
      Rindices = randperm(Nel);
      N10 = floor(Nel/10);
      phi(Rindices(1:N10)) = 1
      nbcon=sum(sum(phi))  
      nb=sum(sum(phi))*rand(1);
      con=[con; nb, nbcon]
  end
  hold on 
  Linecolor = hsv(5);
  plot(con(:,2),con(:,1),'color', Linecolor(simul,:))
  con=[]; 
end

hold off

Thanks a lot !!