Journal on Satisfiability, Boolean Modeling and Computation - Volume 7, issue 2-3
Open Access
ISSN
1574-0617 (E)
The scope of JSAT is propositional reasoning, modeling, and computation. The Satisfiability discipline is a central focus of JSAT. We welcome all sorts of contributions to this theme but also encourage authors to submit papers on related topics as Computational Logic, Constraint Programming, Satisfiability Modulo Theories, Quantified Boolean Logic, Pseudo Boolean Methods, zero-one Programming, Integer Programming and Operations Research, whenever the link to Satisfiability is apparent.
Especially JSAT welcomes substantial extensions of conference papers, where the actual conference contribution must be cited. As such, authors are able to provide more detailed information about their work (theoretical details, proofs or theorems, algorithmic or implementation details, more exhaustive empirical evaluations) which were enforced to be omitted in the conference proceedings simply because of strict page limitations.
JSAT also welcomes detailed descriptions of new promising but challenging applications around SAT, to make the SAT community aware of those new applications, and to provide it the opportunity to tackle those challenges.
Occasionally JSAT also publishes Research Notes. Research Notes are also thoroughly reviewed but are not considered full Journal publications and hence will be designated and must be referenced to as such. Also, JSAT publishes papers on System Descriptions, being contributions with a focus on the internals of a Solver.
Abstract: Sat4j is a mature, open source library of SAT-based solvers in Java. It provides a modular SAT solver architecture designed to work with generic constraints. Such architecture is used to provide SAT, MaxSat and pseudo-boolean and solvers for lightweight constraint programming. Those solvers have been evaluated regularly in the corresponding international competitive events. The library has been adopted by several academic softwares and the widely used Eclipse platform, which relies on a pseudo-boolean solver from Sat4j for its plugins dependencies management since June 2008.
Abstract: We present DepQBF 0.1, a new search-based solver for quantified boolean formulae (QBF). It integrates compact dependency graphs to overcome the restrictions imposed by linear quantifier prefixes of QBFs in prenex conjunctive normal form (PCNF). DepQBF 0.1 was placed first in the main track of QBFEVAL’10 in a score-based ranking. We provide a general system overview and describe selected orthogonal features such as restarts and removal of learnt constraints.
Abstract: The design of a SAT-solver or the modification of an existing one is always followed by a phase of intensive testing of the solver on a benchmark of instances. This task can be very time consuming even when using multi-core computers or computer clusters. To speed up this process we designed EDACC. A system capable of managing solvers with their parameters, instances, creating experiment jobs and running them on arbitrary multi-core systems. After loading solvers and instances into the system the user is able to configure the parameters of the solvers and choose the instances for the experiment and the…settings of the runs. Then EDACC generates the jobs for the experiment and stores them in a database. The user only has to start the EDACC-clients on the target computing system. Each client will load jobs from the database and try to use the full computing capacity of the system to accomplish its tasks. The client will also monitor the resources of the solvers such as time and memory. When a job is finished the client will write the results back to the database and choose another job until all jobs are finished. The clients can be distributed on a grid to increase the throughput. System crashes will not affect the results because the results are saved to a remote database. The user only has to restart the client. With the help of this system, testing and comparing solvers can be done much faster and much more efficiently.
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Keywords: SAT-solver testing, design of tests, computer clusters, jobs scheduling
Abstract: In this paper we outline QuBE7’s main features, describing first the options of the preprocessors, and then giving some details about how the core search-based solver (i) performs unit and pure literal propagation; and (ii) performs the “Conflict Analysis procedure” for non-chronological backtracking, generalised from the SAT to the QBF case. We conclude with the experimental evaluation, showing that QuBE7.0 is the a state-of-the-art single-engine QBF solver.
Abstract: In this paper we analyze three well-known preprocessors for Max-SAT. The first preprocessor is based on the so-called variable saturation . The second preprocessor is based on the resolution mechanism incorporated in modern branch and bound solvers. The third preprocessor is specific for the Maximum Clique problem and other problems with similar encoding in WCNF such as minimum vertex covering and combinatorial auctions . Our experimental investigation is divided in two parts. In the first part, we study the effect of the preprocessors on several problem instances using different metrics. In the second part, the effect of each…preprocessor is analyzed in some of the most relevant Max-SAT local search algorithms of the literature including Gsat , Walksat , Adaptnovelty +, Irots and Saps . Results indicate that some of these algorithms find much better solutions after the preprocessor. Furthermore, some preprocessed instances can be solved to optimality with local search under very specific conditions.
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Keywords: max-SAT, stochastic local search, inference