A Clause-Based Heuristic for SAT Solvers

We propose a new decision heuristic for DPLL-based propositional SAT solvers. Its essence is that both the initial and the conflict clauses are arranged in a list and the next decision variable is chosen from the top-most unsatisfied clause. Various methods of initially organizing the list and movin...

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Bibliographic Details
Published inLecture notes in computer science pp. 46 - 60
Main Authors Dershowitz, Nachum, Hanna, Ziyad, Nadel, Alexander
Format Book Chapter Conference Proceeding
LanguageEnglish
Published Berlin, Heidelberg Springer Berlin Heidelberg 2005
Springer
SeriesLecture Notes in Computer Science
Subjects
Applied sciences
Computer science; control theory; systems
Conjunctive Normal Form Formula
Decision Heuristic
Empty Clause
Exact sciences and technology
Logical, boolean and switching functions
Partial Assignment
Satisfying Assignment
Theoretical computing
Propositional logic
Conjunctive normal form
Constraint satisfaction
Satisfiability
Heuristic method
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Summary:We propose a new decision heuristic for DPLL-based propositional SAT solvers. Its essence is that both the initial and the conflict clauses are arranged in a list and the next decision variable is chosen from the top-most unsatisfied clause. Various methods of initially organizing the list and moving the clauses within it are studied. Our approach is an extension of one used in Berkmin, and adopted by other modern solvers, according to which only conflict clauses are organized in a list, and a literal-scoring-based secondary heuristic is used when there are no more unsatisfied conflict clauses. Our approach, implemented in the 2004 version of zChaff solver and in a generic Chaff-based SAT solver, results in a significant performance boost on hard industrial benchmarks.
ISBN:3540262768
9783540262763
ISSN:0302-9743
1611-3349
DOI:10.1007/11499107_4