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We describe a special purpose computer architecture for the parallel processing of queries, including associative searches, in a dynamic file. The architecture is a highlyparallel network of small processors of two types connected in a full binary tree network. Records are stored in the leaves of the tree; each leaf processor is responsible for records occurring within a rectangular solid part of the space. Queries and record updates are fed into the root of the tree. Internal nodes selectively direct each query and update to leaves so that each leaf sees only the information geometrically close to the records for which it is responsible. File updates cause a reorganization of the tree, which is accomplished in a manner that can accommodate either incremental or massive changes. The architecture can be viewed as a hardware implementation of Bentley's k-d trees. The design is extensible and well-suited to implementation in VLSI.-K< 4 .

ABsrRACTThe performance of the cellular computer proposed by Meg6 has been investigated by programming a number of associative search algorithms and analyzing the time and space required for their execution. The present work describes the results of three different analysis techniques applied to algorithms for nearest neighbor and closest pair problems for files of n points in £-dimensional space.Brute force methods are described for solving the nearest neighbor problem.. If the initial program expression is suitably placed in memory, analysis of the most parallel brute force algorithm yields complexity results of 0(£) time and O(kn) space, These bounds are shown to be asymptotically optimal with respect to the problem and the machine.Brute force, semi-parallel, and divide-and-conquer solutions are described for solving the closest pair problem. Analyses of the best semi-parallel algorithms yield complexity results of O(kn) time and space, which are shown to be asymptotieally optimal.