title: 3-D numpy matrix multiplication in numpy to get 1 D array
body: <p>I've 2 3-D matrix of this form:</p>
  
  <p><code>a = np.random.randint(0, 100, size=(3, 4, 3))</code></p>
  
  <p><code>b = np.random.normal(0, 1, size=(3,3, 4))</code></p>
  
  <p>I want to multiply these 2 matrices, in such a way that I get a matrix of this form:</p>
  
  <p><code>a_b = np.random.normal(0,1,size = (3,1))</code></p>
  
  <p>I can change the matrix shape of <code>b</code> in anyway to get <code>a_b</code> shape. E.g. I can make <code>b 2X2 matrix</code> or change the shape of the matrix in any other way.</p>
  
  <p>Can someone please guide me?</p>
  
  <p>Thanks!</p>