Improved upper and lower time bounds for parallel random access machines without simultaneous writes

Journal Article · Fri Feb 01 04:00:00 EST 1991 · SIAM Journal on Computing (Society for Industrial and Applied Mathematics); (United States)

DOI:https://doi.org/10.1137/0220005· OSTI ID:5993683

Parberry, I ^[1]; Yan, P Y ^[2]

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1. Dept. of Computer Science, Univ. of North Texas, Denton, TX (US)
2. Dept. of Mathematics, Pennsylvania State Univ. University Park, PA (US)

This paper reports on the time required by a variant of the PRAM (a parallel machine model which consists of sequential processors which communicate by reading and writing into a common shared memory) to compute a certain class of functions called critical functions (which include the Boolean OR of n bits). Simultaneous reads from individual cells of the shared memory are permitted, but simultaneous writes are not. It is shown that any PRAm which computes a critical function must take at least 0.5 log n - O(1) steps, and that there exists a critical function which can be computer in 0.57 log n + O(1) steps. These bounds represent an improvement in the constant factor over those previously known.

• OSTI ID: 5993683
• Journal Information: SIAM Journal on Computing (Society for Industrial and Applied Mathematics); (United States), Journal Name: SIAM Journal on Computing (Society for Industrial and Applied Mathematics); (United States) Vol. 20:1; ISSN SMJCA; ISSN 0097-5397
• Country of Publication: United States
• Language: English

Related Subjects

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