title: Numpy - Calculating product of a diagonal
body: <p>Newbie question:  assuming I have a matrix A, is there a numpy function which will calculate the product of the diagonal elements of A?  </p>
  
  <p>EG: </p>
  
  <p><a href="https://i.stack.imgur.com/Zmdri.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Zmdri.png" alt="enter image description here"></a></p>
  
  <p>Where, X(i,i) is the diagonal product of the matrix.  </p>