Adaptive Bitonic Sorting: An Optimal Parallel Algorithm for Shared-Memory Machines

• DOI: 10.1137/0218014
• Publication Date: 2005-02-24T06:32:44Z
• Authors: Gianfranco Bilardi; Alexandru Nicolau
• Keywords: 0102 computer and information sciences; 01 natural sciences

We propose a parallel algorithm, called adaptive bitonic sorting, which runs on a PRAC, a shared-memory multiprocessor where fetch and store conflicts are disallowed. On a $P$ processors PRAC, our algorithm achieves optimal performance $TP = O(N \log N)$, for any computation time $T$ in the range $\Omega (\log^{2} N) \leq T \leq O(N \log N)$. Adaptive bitonic sorting has also a small constant factor, since it performs less than $2N \log N$ comparisons, and only a handful of operations per comparison.