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The ACM Journal of Experimental Algorithmics


Volume 2, Article 2, 1997


Reactive Search, a History-Sensitive Heuristic for Max-Sat

by

Roberto Battiti

and

Marco Protasi

http://www.jea.acm.org/1997/BattitiReactive/

The Reactive Search (RS) method proposes the integration of a simple history-based feedback scheme into local search for the on-line determination of free parameters. In this paper a new RS algorithm is proposed for the approximated solution of the Maximum Satisfiability problem: a component based on local search with temporary prohibitions is complemented with a reactive scheme that determines ("learns") the appropriate value of the prohibition parameter by monitoring the Hamming distance along the search trajectory (algorithm H-RTS). In addition, the non-oblivious functions recently introduced in the framework of approximation algorithms are used to discover a better local optimum in the initial part of the search. The algorithm is developed in two phases. First the bias-diversification properties of individual candidate components are analyzed by extensive empirical evaluation, then a reactive scheme is added to the winning component, based on Tabu Search. The final tests on a benchmark of random Max-3Sat and Max-4Sat problems demonstrate the superiority of H-RTS with respect to alternative heuristics.

Received
Revised
Accepted
Final Revision
Published
June 28, 1996
February 7, 1997
March 11, 1997
April 19, 1997
May 19, 1997

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