Hi,
Very great work! I don't understand the meaning of 
. How the \sqrt{d} is used in the code (_loss_geocross() function)? I am not familar with this function but I think it is very effective in constraining the results. Can you give more details about it? Or can you give me more reference? I found that ref [22] contains so many chapters, I did not find the right place that intrudoced the sphere of radius \sqrt{d}.
Thanks very much.