title: How to add a 2d tensor to every 2d tensor from a 3d tensor
body: <p>I'm trying to add a 2d tensor to every 2d tensor from a 3d tensor.
  Let's say i have a  tensor <code>a</code> with <code>(2,3,2)</code> shape and a tensor <code>b</code> with <code>(2,2)</code> shape.</p>
  
  <pre><code>a = [[[1,2],
        [1,2],
        [1,2]],
       [[3,4],
        [3,4],
        [3,4]]]
  
  b = [[1,2], [3,4]]
  
  #the result i want to get
  a[:, 0, :] + b
  a[:, 1, :] + b
  a[:, 2, :] + b
  </code></pre>
  
  <p>I wanna know if there is a method in pytorch that can do this.</p>