Karloff–Zwick algorithm
Overview
The Karloff-Zwick algorithm in Computational complexity theory presents a randomised approximation algorithm taking an instance of MAX-3SAT as input. If the instance is satisfiable then the expected weight of the assignment found is at least 7/8 of optimal. They provide strong evidence (but not a proof) that the algorithm performs equally well on arbitrary MAX-3SAT instances.
Hastad has shown that, assuming P ≠ NP, no polynomial-time algorithm for MAX 3SAT can achieve a performance ratio exceeding 7/8����, even when restricted to satisfiable instances of the problem. Their algorithm is therefore optimal in this sense.
References
A 7/8-approximation algorithm for MAX 3SAT?
Karloff, H., Zwick, U.
Foundations of Computer Science, 1997. Proceedings., 38th Annual Symposium on
20-22 Oct. 1997 Page(s):406 - 415 J. Hastad. "Some optimal inapproximability results." In proceedings of the 29th ACM STOC, 1-10, 1997