Shellsort and Sorting Networks

Download or read book Shellsort and Sorting Networks written by Vaughan R. Pratt and published by . This book was released on 1972 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shellsort is a particular method of sorting data on digital computers. Associated with each variant of Shellsort is a sequence of integers that characterizes that variant. In the paper the author answers some open questions about the speed of Shellsort with certain characteristic sequences, and suggests a novel application of Shellsort, namely to sorting networks. Shellsort with any characteristic sequence that approximates a geometric progression and that has short coprime subsequences through takes O(n sup 3/2) units of time. For any sequence that approximates a geometric progression with an integer common ratio, this bound is the best possible. However, if the sequence consists of the descending sequence of positive integers less than n and having only 2 and 3 as prime factors, then Shellsort takes only O(n log squared n) units of time. Sorting networks based on Shellsort with this sequence operate approximately 1.5 times as fast as with previous methods. (Author).