title: Store vector in cell of a numpy matrix
body: <p>I am trying to store a vector in the cell of a numpy matrix.</p>
  
  <pre><code>mat=n.zeros((5,5))
  vec=n.zeros(5)
  mat[0][0]=vec
  </code></pre>
  
  <p>And it throws this error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  ValueError: setting an array element with a sequence.
  </code></pre>
  
  <p>What am I doing wrong here? </p>