title: Elementwise subtraction error: In an assignment A(I) = B, the number of elements in B and I must be the same
body: <p>I have two matrices, <code>X</code> and <code>Y</code>, and I want to perform elementwise subtraction. Here's my code:</p>
  
  <pre><code>whos('X', 'Y')
  Z = X - Y;
  </code></pre>
  
  <p>The following output shows the sizes of <code>X</code> and <code>Y</code>, which are identical, but then gives an error message suggesting that they are, in fact, not the same size:</p>
  
  <pre><code>Name          Size             Bytes  Class     Attributes
  
  X          1995x10             159600 double              
  Y          1995x10             159600 double            
  
  In an assignment  A(I) = B, the number of elements in B and I must be
  the same.
  </code></pre>
  
  <p>What could be the reason for this?</p>