Author :
Ferreira, Afonso ; Kenyon, Claire ; Rau-Chaplin, Andrew ; Ubéda, Stéphane
Abstract :
The range tree is a fundamental data structure for multidimensional point sets, and as such, is central in a wide range of geometric and database applications. The authors describe the first non-trivial adaptation of range trees to the parallel distributed memory setting (BSP like models). Given a set L of n points in d-dimensional Cartesian space, they show how to construct on a coarse grained multicomputer a distributed range tree T in time O(s/p+Tc(s,p)), where s=n logd-1 n is the size of the sequential data structure and T,(s, p) is the time to perform an h-relations with h=Θ(s/p). They then show how T can be used to answer a given set Q of m=O(n) range queries in time O(s log n/p+Tc (s,p)) and O(s log n/p+Tc(s,p)+k/p), for the associative-function and report modes respectively, where k is the number of results to be reported. These parallel construction and search algorithms are both highly efficient, in that their running times are the sequential time divided by the number of processors, plus a constant number of parallel communication rounds
Keywords :
computational complexity; computational geometry; database theory; distributed memory systems; parallel algorithms; query processing; search problems; tree data structures; associative-function; coarse grained multicomputer; computation time; d-dimensional Cartesian space; d-dimensional range search; data structure; database applications; distributed range tree; geometric applications; h-relations; multicomputers; multidimensional point sets; parallel construction algorithms; parallel distributed memory setting; parallel search algorithms; processors; range queries; range tree; report modes; running times; sequential data structure; sequential time; Broadcasting; Councils; Distributed computing; Global communication; Parallel algorithms; Parallel machines; Sorting; Spatial databases; Tree data structures; User-generated content;