nsDist3d: Calculate coordinate-specific distance matrices, only for nearest neighbors
and store in an array
Description
nsDist3d generates and returns new 3-dimensional arrays containing
the former dist1_sq, dist2_sq, and dist12 matrices, but
only as needed for the k nearest-neighbors of each location.
these 3D matrices (dist1_3d, dist2_3d, and dist12_3d)
are used in the new implementation of calculateAD_ns().
Arrays with nearest neighbor distances in each coordinate
direction.
Arguments
coords
N x 2 matrix; contains the x-y coordinates of stations.
nID
N x k matrix; contains indices of nearest neighbors.
scale_factor
Scalar; optional argument for re-scaling the distances.
isotropic
Logical; indicates whether distances should be calculated
separately for each coordinate dimension (FALSE) or simultaneously for all
coordinate dimensions (TRUE). isotropic = TRUE can only be used for
two-dimensional coordinate systems.