title: NumPy dot prodoct of a 2d array and a 3D array element wise
body: <pre><code>A = np.array([[1,1],
                [2,2],
                [3,3]])
  
  B = np.array([[[1],[2]],[[3],[4]]])
  </code></pre>
  
  <p>I think of <code>B</code> as an array of 2 matrix, what I want to achieve is to do dot product between <code>A</code> and each element of <code>B</code>, to get:</p>
  
  <pre><code>[[[3],
    [6],
    [9]], 
   [[7],
    [14],
    [21]]]
  </code></pre>
  
  <p>but if I do <code>np.dot(A,B)</code>, I get </p>
  
  <pre><code>[[3,7],
   [6,14],
   [9,21]]
  </code></pre>
  
  <p>how to get what I want here?</p>