Experimental analysis of the fastest optimum cycle ratio and mean algorithms

Abstract

Optimum cycle ratio (OCR) algorithms are fundamental to the performance analysis of (digital or manufacturing) systems with cycles. Some applications in the computer-aided design field include cycle time and slack optimization for circuits, retiming, timing separation analysis, and rate analysis. There are many OCR algorithms, and since a superior time complexity in theory does not mean a superior time complexity in practice, or vice-versa, it is important to know how these algorithms perform in practice on real circuit benchmarks. A recent published study experimentally evaluated almost all the known OCR algorithms, and determined the fastest one among them. This article improves on that study in the following ways: (1) it focuses on the fastest OCR algorithms only; (2) it provides a unified theoretical framework and a few new results; (3) it runs these algorithms on the largest circuit benchmarks available; (4) it compares the algorithms in terms of many properties in addition to running times such as operation counts, convergence behavior, space requirements, generality, simplicity, and robustness; (5) it analyzes the experimental results using statistical techniques and provides asymptotic time complexity of each algorithm in practice; and (6) it provides clear guidance to the use and implementation of these algorithms together with our algorithmic improvements.