An Experimental Study of Word-Level Parallelism in Some Sorting Algorithms
A number of algorithms for fundamental problems such as sorting, searching, priority queues and shortest paths have been proposed recently for the unit-cost RAM with word size w. These algorithms offer dramatic (asymptotic) speedups over classical approaches to these problems. We describe some preliminary steps we have taken towards a systematic evaluation of the practical performance of these algorithms. The results that we obtain are fairly promising. 1. Introduction In classical data structures and algorithms for manipulating sets of ordered keys, it is common to assume that the relative order of two keys can only be determined by comparing them in unit time. While this assumption makes for generality, real computers have many other unit-time operations besides comparisons. Indeed, the hash table, another common data structure, applies unit-time operations other than comparisons to a key (e.g. arithmetic operations to evaluate a hash function) . In order to support unit-time (..