title: Fast ellipsoid(s) intersection algorithm
body: <p>Let's say I've got 1 million arbitrarily shaped, arbitrarily oriented N-dimensional ellipsoids scattered randomly through N-dimensional space.  Given a sub set of ellipsoids, I want to "quickly" determine the set of all ellipsoids that the ellipsoids from the first set intersects.</p>
  
  <p>There's got to be an algorithm for this.  What is it?  What is it's "O" complexity?</p>