title: element wise sum of structured arrays in numpy
body: <p>I wonder if it is possible at all to perform element-wise sum (or other operations) of two structured numpy arrays of an identical shape.</p>
  
  <pre><code>arr1 = np.array([[1,2,3],[2,3,4]], dtype=[("x", "f8"),("y", "f8")])
  arr2 = np.array([[5,4,3],[9,6,4]], dtype=[("x", "f8"),("y", "f8")])
  arr3 = np.sum(arr1, arr2)
  </code></pre>
  
  <p>says "ufunc 'add' did not contain a loop with signature matching types dtype([('x', '
  
  <p>If it is not possible, it will be great to understand why that is impossible or impractical to implement in numpy.</p>