Index Exceeds Matrix Dimensions

When I run the code below I get the error "index exceeds matrix dimensions' I'm trying to plot time on the x-axis and s,i,r on three plots. Thank you

pops=[s;i;r];
for n=1:run_count
   for j=1:n
      % loop to build up matrix of population values 
      lambda=mu*(totpop)+alpha*i;
      news=s+lambda-beta*s*i-mu*s;
      newi=i+beta*s*i-(alpha+k)*i-mu*i+p*r;
      newr=r+k*i-mu*r-p*r;   
      s=news;
      i=newi;
      r=newr; 
      beta=normrnd(2.3e-9,2.3e-9*.1);
      k=normrnd(1.417e-6,1.417e-6*.1);
      p=normrnd(.0024,.0024*.1);
      pops=[pops,[s;i;r]];

     end

    % plot result
  subplot(3, 1, 1);
  plot ([0:n],pops(1,:)); 
  xlabel ('time');
  ylabel ('susceptible');

hold on;

subplot(3, 1, 2);
plot ([0:n], pops(2,:));
xlabel ('time');
ylabel ('infected');

hold on;

subplot(3, 1, 3);
plot ([0:n],pops(3,:));
xlabel ('time');
ylabel ('recovered');

hold on;

    if true
      % code
    end

end

Answer 1

[James Tursa]

You can use the debugger for this. First, type in the following at the command line:

dbstop if error

Then run your code. When the error is encountered, the code will pause at the offending line with all current variables intact. Then you can examine the size of the variables that are causing the problem. Backtrack in your code to figure out why the sizes and/or indexes are not what you expected at that line.