https://doi.org/10.1351/goldbook.11408
A vector that describes a molecular structure in which each element corresponds to a distance (number of bonds in a 2D structure or a binned interatomic
distance in a 3D structure) between atoms of a particular type and the count of the number of times that distance is found in the structure.
Example: A simple autocorrelation vector of a 2D structure might consist of elements corresponding to seven distances (\(\pu{1\!{-}\! 7}\) bond distances) and seven types of atom pairs (\(\ce{C-C}\), \(\ce{C-O}\), \(\ce{C-N}\), \(\ce{C-other}\), \(\ce{O-N}\), \(\ce{O-O}\), \(\ce{N-N}\)).