title: Octave: Calling a function in its function file
body: <p>Is calling a function in the file functions definition file possible? I am pretty curious about it. Thanks for your answers.</p>
  
  <pre><code>%It would prove efficient to write a function since we are going
  %to do the same thing twice.
  function fleas(N);
  clear totalflea;
  %The below vector is for plotting purposes only.
  Nvector = linspace(0, N, N + 1);
  %Define the flea vector as follows:
  %The value 0 correspond to a fleas residing on dog B 
  %(Burnside);thus initially all fleas are on Burnside.
  totalflea(1) = 0;
  %Since initially we do not have any fleas on Burnside.
  fv = zeros(1,50);
  for n = 1 : N;
  k = randi(50);
  %The above code generates a random integer between 1 and 50.
  %The code has been implemented in Octave 3.4.
  switch fv(k)
      case 0
      fv(k) = 1;
      case 1
      fv(k) = 0;
  end
  %The above statement changes the values of fv(k) depending
  %on its initial value. The possible values are 0 or 1.
  totalflea(n + 1) = sum(fv);
  endfor
  %The following lines are there to depict two standard deviations away
  %from the mean value of 25. The standard deviation of a discrete binomial
  %variable is found in "Introduction to Probability" by Bertsekas and
  %Tsitsiklis. The 2 SD barrier is as follows:
  sdp = ones(1, N + 1)*(25 + 2*sqrt(50)/2);
  sdm = ones(1, N + 1)*(25 - 2*sqrt(50)/2);
  plot (Nvector, totalflea, Nvector, sdp , "1", Nvector, sdm, "1");
  % "1" is supplied as an optional argument to determine the color 
  %of the graph.
  xlabel('Time Steps')
  ylabel('Fleas on Anik')
  xrange 
  endfunction
  </code></pre>
  
  <p>This works fine, yet when I append the line fleas(500) for example at the end of the file I get a parse error. When I add it at the beginning of the file I get the following error:</p>
  
  <pre><code>warning: function 'fleas' defined within script file '/home/ongun/Desktop/Dropbox/Computational Physics/Codes/fleas.m'
  error: invalid use of script /home/ongun/Desktop/Dropbox/Computational Physics/Codes/fleas.m in index expression
  </code></pre>