KD-tree classes and adaptors

Collaboration diagram for KD-tree classes and adaptors:

Classes
class	nanoflann::KDTreeSingleIndexAdaptor
	kd-tree index More...
struct	nanoflann::KDTreeEigenMatrixAdaptor
	A simple KD-tree adaptor for working with data directly stored in an Eigen Matrix, without duplicating the data storage. More...