@misc{GebserKaufmannSchaub2012,
  author    = {Gebser, Martin and Kaufmann, Benjamin and Schaub, Torsten H.},
  title     = {Multi-threaded ASP solving with clasp},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {586},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-41397},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-413977},
  pages     = {21},
  year      = {2012},
  abstract  = {We present the new multi-threaded version of the state-of-the-art answer set solver clasp. We detail its component and communication architecture and illustrate how they support the principal functionalities of clasp. Also, we provide some insights into the data representation used for different constraint types handled by clasp. All this is accompanied by an extensive experimental analysis of the major features related to multi-threading in clasp.},
  language  = {en}
}
@misc{HoosKaminskiLindaueretal.2015,
  author    = {Hoos, Holger and Kaminski, Roland and Lindauer, Marius and Schaub, Torsten H.},
  title     = {aspeed},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {588},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-41474},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-414743},
  pages     = {26},
  year      = {2015},
  abstract  = {Although Boolean Constraint Technology has made tremendous progress over the last decade, the efficacy of state-of-the-art solvers is known to vary considerably across different types of problem instances, and is known to depend strongly on algorithm parameters. This problem was addressed by means of a simple, yet effective approach using handmade, uniform, and unordered schedules of multiple solvers in ppfolio, which showed very impressive performance in the 2011 Satisfiability Testing (SAT) Competition. Inspired by this, we take advantage of the modeling and solving capacities of Answer Set Programming (ASP) to automatically determine more refined, that is, nonuniform and ordered solver schedules from the existing benchmarking data. We begin by formulating the determination of such schedules as multi-criteria optimization problems and provide corresponding ASP encodings. The resulting encodings are easily customizable for different settings, and the computation of optimum schedules can mostly be done in the blink of an eye, even when dealing with large runtime data sets stemming from many solvers on hundreds to thousands of instances. Also, the fact that our approach can be customized easily enabled us to swiftly adapt it to generate parallel schedules for multi-processor machines.},
  language  = {en}
}
@misc{GebserHarrisonKaminskietal.2015,
  author    = {Gebser, Martin and Harrison, Amelia and Kaminski, Roland and Lifschitz, Vladimir and Schaub, Torsten H.},
  title     = {Abstract gringo},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {592},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-41475},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-414751},
  pages     = {15},
  year      = {2015},
  abstract  = {This paper defines the syntax and semantics of the input language of the ASP grounder gringo. The definition covers several constructs that were not discussed in earlier work on the semantics of that language, including intervals, pools, division of integers, aggregates with non-numeric values, and lparse-style aggregate expressions. The definition is abstract in the sense that it disregards some details related to representing programs by strings of ASCII characters. It serves as a specification for gringo from Version 4.5 on.},
  language  = {en}
}
@misc{GebserLeeLierler2011,
  author    = {Gebser, Martin and Lee, Joohyung and Lierler, Yuliya},
  title     = {On elementary loops of logic programs},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {566},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-41309},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-413091},
  pages     = {36},
  year      = {2011},
  abstract  = {Using the notion of an elementary loop, Gebser and Schaub (2005. Proceedings of the Eighth International Conference on Logic Programming and Nonmonotonic Reasoning (LPNMR'05 ), 53-65) refined the theorem on loop formulas attributable to Lin and Zhao (2004) by considering loop formulas of elementary loops only. In this paper, we reformulate the definition of an elementary loop, extend it to disjunctive programs, and study several properties of elementary loops, including how maximal elementary loops are related to minimal unfounded sets. The results provide useful insights into the stable model semantics in terms of elementary loops. For a nondisjunctive program, using a graph-theoretic characterization of an elementary loop, we show that the problem of recognizing an elementary loop is tractable. On the other hand, we also show that the corresponding problem is coNP-complete for a disjunctive program. Based on the notion of an elementary loop, we present the class of Head-Elementary-loop-Free (HEF) programs, which strictly generalizes the class of Head-Cycle-Free (HCF) programs attributable to Ben-Eliyahu and Dechter (1994. Annals of Mathematics and Artificial Intelligence 12, 53-87). Like an HCF program, an HEF program can be turned into an equivalent nondisjunctive program in polynomial time by shifting head atoms into the body.},
  language  = {en}
}