title: numpy dot behaving strange
body: <p>I'm new to <code>numpy</code>. So I have a very simple matrix factor multiplication, something as follows:</p>
  
  <pre><code>vecT = np.dot(matDT, vecGradU) 
  </code></pre>
  
  <p>Now depending on the input, sometimes this results in a column vector</p>
  
  <pre><code>print("matDT -&gt; ", matDT.shape)
  print("vecGradU -&gt; ", vecGradU.shape)
  print("vecT -&gt; ", vecT.shape)
  </code></pre>
  
  <p>These are the results for one input:</p>
  
  <pre><code>matDT -&gt;  (4, 4)
  vecGradU -&gt;  (4,)
  vecT -&gt;  (4,)
  </code></pre>
  
  <p>for another input</p>
  
  <pre><code>matDT -&gt;  (9, 9)
  vecGradU -&gt;  (9,)
  vecT -&gt;  (1, 9)
  </code></pre>
  
  <p>Why would the <code>dot</code> function behave differently?</p>