title: Eigendecomposition in tensorflow from python API
body: <p>What would be the best way to achieve an iterative eigendecomposition using TensorFlow? (something like matlabs eigs).</p>
  
  <p>I know that Eigen has the ability to perform an eigendecomposition, but it is unclear to me how to access this from the tensorflow python API. If tensorflow is just acting as an API to Eigen, then would there be any advantage over simply using scipy.sparse.linalg.eigs?</p>