title: How to go from np.tensordot to np.einsum
body: <p>What I have in the code I was given is something like:</p>
  
  <pre><code>C = np.tensordot(B, A, axes = (0,0))
  </code></pre>
  
  <p>A is a <code>(20L, 50L)</code> and B is <code>(20L, 20L)</code></p>
  
  <p>I was supposed to change since someone told me it would be faster with <code>np.einsum</code>, but I guess I don't fully understand what <code>tensordot</code> is outputing. </p>
  
  <p>Right now C is a <code>(20L, 50L)</code> and I don't understand why?</p>
  
  <p>Of course I have read the documentation page, but still didn't grasp the information. Take into consideration that I have just started working with Python.</p>