Evaluating Answer Set Programming with Non-Convex Recursive Aggregates

Alviano, Mario

doi:10.3233/fi-2016-1441

Cited by 6 publications

(6 citation statements)

References 41 publications

(72 reference statements)

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“…The proposed algorithm takes advantage of unsatisfiable core analysis, and showed to be very efficient in many cases. As a final remark, we stress here that the algorithm presented in this paper can be nicely combined with the tool lp2sat in order to enumerate models of circumscribed answer set programming theories (under the restriction that answer set existence can be checked in NP; Alviano and Faber 2013); within this respect, completion of disjunctive logic programs (Alviano and Dodaro 2016c), specialized techniques to handle recursive aggregates Alviano 2016), and other algorithms implemented in efficient solvers such as cmodels (Giunchiglia et al 2004, clasp (Gebser et al 2012(Gebser et al , 2015, dlv (Leone et al 2006;Alviano et al 2017) and wasp (Dodaro et al 2011;) may also been employed.…”

Section: Resultsmentioning

confidence: 99%

Model enumeration in propositional circumscription via unsatisfiable core analysis

Alviano¹

2017

Theory and Practice of Logic Programming

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Many practical problems are characterized by a preference relation over admissible solutions, where preferred solutions are minimal in some sense. For example, a preferred diagnosis usually comprises a minimal set of reasons that is sufficient to cause the observed anomaly. Alternatively, a minimal correction subset comprises a minimal set of reasons whose deletion is sufficient to eliminate the observed anomaly. Circumscription formalizes such preference relations by associating propositional theories with minimal models. The resulting enumeration problem is addressed here by means of a new algorithm taking advantage of unsatisfiable core analysis. Empirical evidence of the efficiency of the algorithm is given by comparing the performance of the resulting solver, CIRCUMSCRIPTINO, with HCLASP, CAMUS MCS, LBX and MCSLS on the enumeration of minimal models for problems originating from practical applications.

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Section: Resultsmentioning

confidence: 99%

Model enumeration in propositional circumscription via unsatisfiable core analysis

Alviano¹

2017

Theory and Practice of Logic Programming

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“…Our rewriting uses the saturation technique, similar to the one by Alviano et al (2015) (cf. also Alviano (2016)), who translated nonmonotonic (cyclic) aggregates to disjunctions. However, an important difference to our approach is that they support only a fixed set of traditional aggregates (such as minimum, maximum, etc) whose semantics is directly exploited in a hard-coded fashion in their rewriting, while our approach is generic and thus more flexible.…”

Section: Redl 7 Discussion and Conclusionmentioning

confidence: 99%

Inlining External Sources in Answer Set Programs

Redl¹

2019

Theory and Practice of Logic Programming

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HEX-programs are an extension of answer set programs (ASP) with external sources. To this end, external atoms provide a bidirectional interface between the program and an external source. The traditional evaluation algorithm for HEX-programs is based on guessing truth values of external atoms and verifying them by explicit calls of the external source. The approach was optimized by techniques that reduce the number of necessary verification calls or speed them up, but the remaining external calls are still expensive. In this paper we present an alternative evaluation approach based on inlining of external atoms, motivated by existing but less general approaches for specialized formalisms such as DL-programs. External atoms are then compiled away such that no verification calls are necessary. The approach is implemented in the dlvhex reasoner. Experiments show a significant performance gain. Besides performance improvements, we further exploit inlining for extending previous (semantic) characterizations of program equivalence from ASP to HEX-programs, including those of strong equivalence, uniform equivalence and H, B -equivalence. Finally, based on these equivalence criteria, we characterize also inconsistency of programs wrt. extensions. Since well-known ASP extensions (such as constraint ASP) are special cases of HEX, the results are interesting beyond the particular formalism.Under consideration in Theory and Practice of Logic Programming (TPLP).

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“…For the company control problem, our incremental program in DistAlgo (v.1.1.0b15 on Python 3.7) was the fastest; followed by clingo (v.5.4.0), about 7 times slower; followed by XSB (v.3.8.0), our straightforward program in DistAlgo, and DLV (https://www.dbai.tuwien.ac.at/proj/dlv/dlvRecAggr/ (accessed 2020-09-21)) 1 , each asymptotically and drastically slower than the preceding one. Most recent investigation found that changing the order of hypotheses in rules in XSB can improve the running times for this problem asymptotically.…”

Section: Methodsmentioning

confidence: 99%

“…We briefly state several important properties of the semantics; detailed statements and proofs are in [44]. (1) Consistency: The founded model and constraint models of a program π are consistent. (2) Correctness: The founded model of a program π is a model of π and Cmpl (π).…”

Section: Properties Of the Semanticsmentioning

confidence: 99%

Recursive Rules with Aggregation: A Simple Unified Semantics

Liu

Stoller

2021

Lecture Notes in Computer Science

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Complex reasoning problems are most clearly and easily specified using logical rules, but require recursive rules with aggregation such as counts and sums for practical applications. Unfortunately, the meaning of such rules has been a significant challenge, leading to many disagreeing semantics.This paper describes a unified semantics for recursive rules with aggregation, extending the unified founded semantics and constraint semantics for recursive rules with negation. The key idea is to support simple expression of the different assumptions underlying different semantics, and orthogonally interpret aggregation operations using their simple usual meaning. We present formal definition of the semantics, prove important properties of the semantics, and compare with prior semantics. In particular, we present an efficient inference over aggregation that gives precise answers to all examples we have studied from the literature. We also applied our semantics to a wide range of challenging examples, and performed experiments on the most challenging ones, all confirming our analyzed results.

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Evaluating Answer Set Programming with Non-Convex Recursive Aggregates

Cited by 6 publications

References 41 publications

Model enumeration in propositional circumscription via unsatisfiable core analysis

Model enumeration in propositional circumscription via unsatisfiable core analysis

Inlining External Sources in Answer Set Programs

Recursive Rules with Aggregation: A Simple Unified Semantics

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