Counting distance permutations

Matthew Skala
2008 2008 IEEE 24th International Conference on Data Engineering Workshop  
Distance permutation indexes support fast proximity searching in high-dimensional metric spaces. Given some fixed reference sites, for each point in a database the index stores a permutation naming the closest site, the second-closest, and so on. We examine how many distinct permutations can occur as a function of the number of sites and the size of the space. We give theoretical results for tree metrics and vector spaces with L 1 , L 2 , and L ∞ metrics, improving on the previous best known
more » ... rage space in the vector case. We also give experimental results and commentary on the number of distance permutations that actually occur in a variety of vector, string, and document databases.
doi:10.1109/icdew.2008.4498346 dblp:conf/icde/Skala08 fatcat:akk2yiyjgjdkvctfbnn7wokjse