title: Consider preallocating for speed
body: <p>I was doing the following</p>
  
  <pre><code>for i = 1:m,
      index = 0;
      for j = 1:n,
          index = index+values(i,j)*2^(j-1);
          if (j==1)
              symbol_chip = chip_values(index+1,:);
          else
              symbol_chip = [symbol_chip chip_values(index+1,:)];
          end
      end
  end
  </code></pre>
  
  <p>it tells me the following:</p>
  
  <blockquote>
    <p><code>symbol_chip</code> might be growing inside the loop. Consider preallocating for speed.</p>
  </blockquote>
  
  <p>Any ideas?</p>