Fast Nearest Neighbor Search Algorithms and Applications
Alina Beygelzimer, Sham Kakadet and John Langford (cover tree library), 
        Sunil Arya and David Mount (ANN library 1.1.2 for the kd-tree approach), Shengqiao Li
ANN Copyright (c) 1997-2010 University of Maryland and Sunil
Arya and David Mount. All Rights Reserved.
Cover-tree and kd-tree fast k-nearest neighbor search algorithms and related applications
        including KNN classification, regression and information measures are implemented.