Improved Local Search for Circuit Satisfiability

Belov, Anton; Stachniak, Zbigniew

doi:10.1007/978-3-642-14186-7_24

Cited by 6 publications

(9 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Local search algorithms have borrowed techniques from CDCL. For example, unit propagation has been employed [6,8,2], and clause learning as also been used [1]. However, such solvers are usually limited to demonstrating satisfiability, and often cannot be used to reliably prove UNSAT.…”

Section: Supported By Natural Sciences and Engineering Research Councmentioning

confidence: 99%

Off the Trail: Re-examining the CDCL Algorithm

Goultiaeva

Bacchus

2012

Theory and Applications of Satisfiability Testing – SAT 2012

View full text Add to dashboard Cite

Abstract. Most state of the art SAT solvers for industrial problems are based on the Conflict Driven Clause Learning (CDCL) paradigm. Although this paradigm evolved from the systematic DPLL search algorithm, modern techniques of far backtracking and restarts make CDCL solvers non-systematic. CDCL solvers do not systematically examine all possible truth assignments as does DPLL.Local search solvers are also non-systematic and in this paper we show that CDCL can be reformulated as a local search algorithm: a local search algorithm that through clause learning is able to prove UNSAT. We show that the standard formulation of CDCL as a backtracking search algorithm and our new formulation of CDCL as a local search algorithm are equivalent, up to tie breaking.In the new formulation of CDCL as local search, the trail no longer plays a central role in the algorithm. Instead, the ordering of the literals on the trail is only a mechanism for efficiently controlling clause learning. This changes the paradigm and opens up avenues for further research and algorithm design. For example, in QBF the quantifier places restrictions on the ordering of variables on the trail. By making the trail less important, an extension of our local search algorithm to QBF may provide a way of reducing the impact of these variable ordering restrictions.

show abstract

Section: Supported By Natural Sciences and Engineering Research Councmentioning

confidence: 99%

Off the Trail: Re-examining the CDCL Algorithm

Goultiaeva

Bacchus

2012

Theory and Applications of Satisfiability Testing – SAT 2012

View full text Add to dashboard Cite

show abstract

“…CRSAT is an SLS-based SAT algorithm for Boolean circuits that operates directly on circuit structure -that is, without the conversion to CNF. The algorithm was first described in [5] and was subsequently analyzed theoretically and improved in [6]. In this section we provide a high-level overview of the algorithm, and refer the reader to [5,6] for additional details.…”

Section: Crsat: Justification-based Sls With Forward Propagationmentioning

confidence: 99%

“…It has been recognized that one possibility to push further the efficiency of SLS techniques is to develop search techniques that exploit the structure of constraint satisfaction problems. Indeed, various structure-exploiting SLS methods have been developed (among others) for generic constraint satisfaction problems (CSPs; for examples see [1,2,18,10]) and Boolean satisfiability (SAT; for examples see [16,20,21,17,19,14,13,22,4,5]).…”

Section: Introductionmentioning

confidence: 99%

“…To the best of our knowledge, currently the best performing SLS method aimed at industrial SAT instances is CRSAT [5,6]. Instead of working on the rather low conjuctive normal form (CNF) level, CRSAT searches for a solution directly on the level of arbitrary propositional formulas, relying on the compact representation form of Boolean circuits for a succinct way of representing propositional formulas.…”

Section: Introductionmentioning

confidence: 99%

“…Instead of working on the rather low conjuctive normal form (CNF) level, CRSAT searches for a solution directly on the level of arbitrary propositional formulas, relying on the compact representation form of Boolean circuits for a succinct way of representing propositional formulas. Furthermore, instead of relying on restricting search to input variables, as often has been proposed [16,20,21,17,19], CRSAT is based on the justification-based circuit-level SLS approach [14,13], searching over the whole subformula structure, and incorporates a limited form of directed circuit-level Boolean constraint propagation to further exploit structural aspects of the input formulas [5].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Structure-Based Local Search Heuristics for Circuit-Level Boolean Satisfiability

Belov,

Järvisalo

2011

Preprint

Self Cite

View full text Add to dashboard Cite

This work focuses on improving state-of-the-art in stochastic local search (SLS) for solving Boolean satisfiability (SAT) instances arising from realworld industrial SAT application domains. The recently introduced SLS method CRSAT has been shown to noticeably improve on previously suggested SLS techniques in solving such real-world instances by combining justification-based local search with limited Boolean constraint propagation on the non-clausal formula representation form of Boolean circuits. In this work, we study possibilities of further improving the performance of CRSAT by exploiting circuit-level structural knowledge for developing new search heuristics for CRSAT. To this end, we introduce and experimentally evaluate a variety of search heuristics, many of which are motivated by circuit-level heuristics originally developed in completely different contexts, e.g., for electronic design automation applications. To the best of our knowledge, most of the heuristics are novel in the context of SLS for SAT and, more generally, SLS for constraint satisfaction problems.

show abstract

On the Violation of Circuits in Decomposable Negation Normal Form

Bordeaux

Narodytska

2012

Lecture Notes in Computer Science

View full text Add to dashboard Cite

Improved Local Search for Circuit Satisfiability

Cited by 6 publications

References 5 publications

Off the Trail: Re-examining the CDCL Algorithm

Off the Trail: Re-examining the CDCL Algorithm

Structure-Based Local Search Heuristics for Circuit-Level Boolean Satisfiability

On the Violation of Circuits in Decomposable Negation Normal Form

Contact Info

Product

Resources

About