Counting distance permutations
Journal of Discrete Algorithms
Metric Index: An Efficient and Scalable Solution for Similarity Search
SISAP '09 Proceedings of the 2009 Second International Workshop on Similarity Search and Applications
Versatile probability-based indexing for approximate similarity search
Proceedings of the Fourth International Conference on SImilarity Search and APplications
| Hi-index | 0.00 |
A distance permutation index supports fast proximity searching in a high-dimensional metric space. 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_8$ metrics, improving on the previous best known storage 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 spaces.