An Improved Parallel Prefix Sums Algorithm

Abstract

The prefix sums problem for an array [Formula: see text] is to compute all sums [Formula: see text], [Formula: see text]. In this paper, we introduce an improvement for the best previous algorithm that runs in [Formula: see text] time using [Formula: see text] processors on a Sum Concurrent Read Concurrent Write, Parallel Random Access Machine (Sum-CRCW PRAM). The improvements include (1) reducing the total number of operations and (2) reducing the amount of storage required by the algorithm.