title: Broadcast of tensor division by a matrix
body: <p>I was trying to compute the value of a 600x400x100 tensor A divided by 600x400 matrix B along the 3rd axis. You can imagine a video clip of 100 frames, and each 600x400 frames is doing an element-wise division. My code is like:</p>
  
  <pre class="lang-py prettyprint-override"><code>A/B
  </code></pre>
  
  <p>And the error message says:<br>
  <em>ValueError: operands could not be broadcast together with shapes (600,400,129) (600,400)</em><br>
  What's wrong with my codes?</p>