title: Best GPU algorithm for calculating lists of neighbours
body: <p>Given a collection of thousands of points in 3D, I need to get the list of neighbours for each particle that fall inside some cutoff value (in terms of euclidean distance), and if possible, sorted from nearest fo farthest. </p>
  
  <p>Which is the fastest GPU algorithm for this purpose in the CUDA or OpenCL languages? </p>