Optimal parallel merging and sorting without memory conflicts

Journal Article · Sun Nov 01 04:00:00 EST 1987 · IEEE Trans. Comput.; (United States)

DOI:https://doi.org/10.1109/TC.1987.5009478· OSTI ID:5912451

Akl, S G; Santoro, N

A parallel algorithm is described for merging two sorted vectors of total length N. The algorithm runs on a shared-memory model of parallel computation that disallows more than one processor to simultaneously read from or write into the same memory location. It uses kappa processors, where 1 less than or equal to kappa less than or equal to N, and requires O(N/kappa + log kappa x log N) time. The proposed approach for merging leads to a parallel sorting algorithm that sorts a vector of length N in O((log/sup 2/ kappa + N/kappa) log N) time. Because they modify their behavior, and hence their running time, according to the number of available processors, the two new algorithms are said to be self-reconfiguring. In addition, both algorithms are optimal, for kappa less than or equal to N/log/sup 2/ N, in view of the ..cap omega..(N) and ..cap omega..(N log N) lower bounds on merging and sorting, respectively.

• Research Organization: Dept. of Computing and Information Science, Queen's Univ., Kingston, Ont. K7L 3N6
• OSTI ID: 5912451
• Journal Information: IEEE Trans. Comput.; (United States), Journal Name: IEEE Trans. Comput.; (United States) Vol. C-36:11; ISSN ITCOB
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
990210* -- Supercomputers-- (1987-1989)
ALGORITHMS
ARRAY PROCESSORS
COMPUTERIZED SIMULATION
MATHEMATICAL LOGIC
OPTIMIZATION
PARALLEL PROCESSING
PROGRAMMING
SIMULATION
SORTING
VECTOR PROCESSING