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27th international symposium on logic-based program synthesis and transformation (LOPSTR)

作者： Bodini, Olivier Tarau, Paul UMR CNRS 7030 Lab Informat Paris Nord Paris France Univ North Texas Dept Comp Sci & Engn Denton TX 76203 USA

ISBN: (纸本)9783319944609;9783319944593

Uniquely closable skeletons of lambda terms are Motzkintrees that predetermine the unique closed lambda term that can be obtained by labeling their leaves with de Bruijn indices. Likewise, uniquely typable skeletons of closed lambda terms predetermine the unique simply-typed lambda term that can be obtained by labeling their leaves with de Bruijn indices. We derive, through a sequence of logic program transformations, efficient code for their combinatorial generation and study their statistical properties. As a result, we obtain context-free grammars describing closable and uniquely closable skeletons of lambda terms, opening the door for their in-depth study with tools from analytic combinatorics. Our empirical study of the more difficult case of (uniquely) typable terms reveals some interesting open problems about their density and asymptotic behavior. As a connection between the two classes of terms, we also show that uniquely typable closed lambda term skeletons of size 3n + 1 are in a bijection with binary trees of size n.

关键词： Deriving efficient logic programs logic programming and computational mathematics Combinatorics of lambda terms Inferring simple types Uniquely closable lambda term skeletons Uniquely typable lambda term skeletons

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Multivariant Assertion-based Guidance in Abstract Interpretation 28th

Multivariant Assertion-Based Guidance in Abstract Interpreta...

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28th international symposium on logic-based program synthesis and transformation (LOPSTR(

作者： Garcia-Contreras, Isabel Morales, Jose F. Hermenegildo, Manuel, V IMDEA Software Inst Madrid Spain Univ Politecn Madrid UPM Madrid Spain

ISBN: (纸本)9783030138387;9783030138370

Approximations during program analysis are a necessary evil, as they ensure essential properties, such as soundness and termination of the analysis, but they also imply not always producing useful results. Automatic techniques have been studied to prevent precision loss, typically at the expense of larger resource consumption. In both cases (i.e., when analysis produces inaccurate results and when resource consumption is too high), it is necessary to have some means for users to provide information to guide analysis and thus improve precision and/or performance. We present techniques for supporting within an abstract interpretation framework a rich set of assertions that can deal with multivariance/context-sensitivity, and can handle different run-time semantics for those assertions that cannot be discharged at compile time. We show how the proposed approach can be applied to both improving precision and accelerating analysis. We also provide some formal results on the effects of such assertions on the analysis results.

关键词： program analysis Multivariance Context sensitivity Abstract interpretation Assertions Static analysis User guidance

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Type-based homeomorphic embedding and its applications to online partial evaluation

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17th international symposium on logic-based program synthesis and transformation

作者： Albert, Elvira Gallagher, John Gomez-Zamalloa, Miguel Puebla, German Univ Complutense Madrid DSIC E-28040 Madrid Spain Roskilde Univ CBIT DK-4000 Roskilde Denmark Tech Univ Madrid CLIP E-28660 Madrid Spain

ISBN: (纸本)9783540787686

Homeomorphic Embedding (HEm) has proven to be very powerful for supervising termination of computations, provided that such computations are performed over a finite signature, i.e., the number of constants and function symbols involved is finite. However, there are situations, for example numeric computations, which involve an infinite (or too large) signature, in which HEm does not guarantee termination. Some extensions to HEm for the case of infinite signatures have been proposed which guarantee termination, but they either do not provide systematic means for generating such extensions or the extensions are too simplistic and do not produce the expected results in practice. We introduce Type-based Homeomorphic Embedding (TbHEm) as an extension of the standard, untyped HEm to deal with infinite signatures. In the paper, we show how TbHEm can be used to improve the accuracy of online partial evaluation. For this purpose, we propose an approach to constructing suitable types for partial evaluation automatically based on existing analysis tools for constraint logic programs. We also present useful properties of types which allow us to take full advantage of TbHEm in practice. Experimental results are reported which show that our work improves the state of the practice of online partial evaluation.

关键词： logic programming

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Efficient synthesis of out-of-core algorithms using a nonlinear optimization solver

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JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING 2006年第5期66卷 659-673页

作者： Krishnan, S Krishnamoorthy, S Baumgartner, G Lam, CC Ramanujam, J Sadayappan, P Choppella, V Ohio State Univ Dept Comp Sci & Engn Columbus OH 43210 USA Louisiana State Univ Dept Comp Sci Baton Rouge LA 70803 USA Louisiana State Univ Dept Elect & Comp Engn Baton Rouge LA USA Indian Inst Informat Technol & Management Thiruvananthapuram 695581 Kerala India

We address the problem of efficient out-of-core code generation for a special class of imperfectly nested loops encoding tensor contractions arising in quantum chemistry computations. these loops operate on arrays too large to fit in physical memory. the problem involves determining optimal tiling of loops and placement of disk I/O statements. this entails a search in an explosively large parameter space. We formulate the problem as a nonlinear optimization problem and use a discrete constraint solver to generate optimized out-of-core code. the solution generated using the discrete constraint solver consistently outperforms other approaches by up to a factor of four. Measurements on sequential and parallel versions of the generated code demonstrate the effectiveness of the approach. (c) 2005 Published by Elsevier Inc.

关键词： data locality optimization out-of-core algorithms program transformation compiler optimization discrete constrained search tensor contractions

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A Hiking Trip through the Orders of Magnitude: Deriving Efficient Generators for Closed Simply-Typed Lambda Terms and Normal Forms 26th

A Hiking Trip Through the Orders of Magnitude: Deriving Effi...

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26th international symposium on logic-based program synthesis and transformation (LOPSTR)

作者： Tarau, Paul Univ North Texas Dept Comp Sci & Engn Denton TX 76203 USA

ISBN: (纸本)9783319631394;9783319631387

Contrary to several other families of lambda terms, no closed formula or generating function is known and none of the sophisticated techniques devised in analytic combinatorics can currently help with counting or generating the set of simply-typed closed lambda terms of a given size. Moreover, their asymptotic scarcity among the set of closed lambda terms makes counting them via brute force generation and type inference quickly intractable, with previous published work showing counts for them only up to size 10. By taking advantage of the synergy between logic variables, unification with occurs check and efficient backtracking in today's Prolog systems, we climb 4 orders of magnitude above previously known counts by deriving progressively faster Horn Clause programs that generate and/or count the set of closed simply-typed lambda terms of sizes up to 14. A similar count for closed simply-typed normal forms is also derived up to size 14.

关键词： logic programming transformations Type inference Combinatorics of lambda terms Simply-typed lambda calculus Simply-typed normal forms

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A Productivity Checker for logic programming 26th

A Productivity Checker for Logic Programming

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26th international symposium on logic-based program synthesis and transformation (LOPSTR)

作者： Komendantskaya, Ekaterina Johann, Patricia Schmidt, Martin Heriot Watt Univ Edinburgh Midlothian Scotland Appalachian State Univ Boone NC 28608 USA Univ Osnabruck Osnabruck Germany

ISBN: (纸本)9783319631394;9783319631387

Automated analysis of recursive derivations in logic programming is known to be a hard problem. Both termination and non-termination are undecidable problems in Turing-complete languages. However, some declarative languages offer a practical work-around for this problem, by making a clear distinction between whether a program is meant to be understood inductively or coinductively. For programs meant to be understood inductively, termination must be guaranteed, whereas for programs meant to be understood coinductively, productive non-termination (or "productivity") must be ensured. In practice, such classification helps to better understand and implement some non-terminating computations. logic programming was one of the first declarative languages to make this distinction: in the 1980's, Lloyd and van Emden's "computations at infinity" captured the big-step operational semantics of derivations that produce infinite terms as answers. In modern terms, computations at infinity describe "global productivity" of computations in logic programming. Most programming languages featuring coinduction also provide an observational, or small-step, notion of productivity as a computational counterpart to global productivity. this kind of productivity is ensured by checking that finite initial fragments of infinite computations can always be observed to produce finite portions of their infinite answer terms. In this paper we introduce a notion of observational productivity for logic programming as an algorithmic approximation of global productivity, give an effective procedure for semi-deciding observational productivity, and offer an implemented automated observational productivity checker for logic programs.

关键词： logic programming Corecursion Coinduction Termination Productivity

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An Assertion Language for Slicing Constraint logic Languages 28th

An Assertion Language for Slicing Constraint Logic Languages

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28th international symposium on logic-based program synthesis and transformation (LOPSTR(

作者： Falaschi, Moreno Olarte, Carlos Univ Siena Dept Informat Engn & Math Siena Italy Univ Fed Rio Grande do Norte ECT Natal RN Brazil

ISBN: (纸本)9783030138387;9783030138370

Constraint logic programming (CLP) is a language scheme for combining two declarative paradigms: constraint solving and logic programming. Concurrent Constraint programming (CCP) is a declarative model for concurrency where agents interact by telling and asking constraints in a shared store. In a previous paper, we developed a framework for dynamic slicing of CCP where the user first identifies that a (partial) computation is wrong. then, she marks (selects) some parts of the final state corresponding to the data (constraints) and processes that she wants to study more deeply. An automatic process of slicing begins, and the partial computation is "depurated" by removing irrelevant information. In this paper we give two major contributions. First, we extend the framework to CLP, thus generalizing the previous work. Second, we provide an assertion language suitable for both, CCP and CLP, which allows the user to specify some properties of the computations in her program. If a state in a computation does not satisfy an assertion then some "wrong" information is identified and an automatic slicing process can start. We thus make one step further towards automatizing the slicing process. We show that our framework can be integrated with the previous semi-automatic one, giving the user more choices and flexibility. We show by means of examples and experiments the usefulness of our approach.

关键词： Concurrent Constraint programming Constraint logic programming Dynamic slicing Debugging Assertion language

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Non-leftmost unfolding in partial evaluation of logic programs with impure predicates

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15th international symposium on logic based program synthesis and transformation

作者： Albert, Elvira Puebla, German Gallagher, John P. Univ Complutense Madrid Sch Comp Sci E-28040 Madrid Spain Tech U Madrid Sch Comp Sci Madrid Spain Roskilde Univ Dept Comp Sci DK-4000 Roskilde Denmark

ISBN: (纸本)3540326545

Partial evaluation of logic programs which contain impure predicates poses non-trivial challenges. Impure predicates include those which produce side-effects, raise errors (or exceptions), and those whose truth value varies according to the degree of instantiation of arguments. In particular, non-leftmost unfolding steps can produce incorrect results since the independence of the computation rule no longer holds in the presence of impure predicates. Existing proposals allow non-leftmost unfolding steps, but at the cost of accuracy: bindings and failure are not propagated backwards to predicates which are potentially impure. In this work we propose a partial evaluation scheme which substantially reduces the situations in which such backpropagation has to be avoided. With this aim, our partial evaluator takes into account the information about purity of predicates expressed in terms of assertions. this allows some optimizations which are not feasible using existing partial evaluation techniques. We argue that our proposal goes beyond existing ones in that it is a) accurate, since the classification of pure vs impure is done at the level of atoms instead of predicates, b) extensible, as the information about purity can be added to programs using assertions without having to modify the partial evaluator itself, and c) automatic, since (backwards) analysis can be used to automatically infer the required assertions. Our approach has been implemented in the context of CiaoPP, the abstract interpretation-based preprocessor of the Ciao logic programming system.

关键词： logic programming

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Context Generation from Formal Specifications for C Analysis Tools 27th

Context Generation from Formal Specifications for C Analysis...

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27th international symposium on logic-based program synthesis and transformation (LOPSTR)

作者： Alberti, Michele Signoles, Julien TrustInSoft Paris France CEA LIST Software Reliabil & Secur Lab F-91191 Gif Sur Yvette France

ISBN: (纸本)9783319944609;9783319944593

Analysis tools like abstract interpreters, symbolic execution tools and testing tools usually require a proper context to give useful results when analyzing a particular function. Such a context initializes the function parameters and global variables to comply with function requirements. However it may be error-prone to write it by hand: the handwritten context might contain bugs or not match the intended specification. A more robust approach is to specify the context in a dedicated specification language, and hold the analysis tools to support it properly. this may mean to put significant development efforts for enhancing the tools, something that is often not feasible if ever possible. this paper presents a way to systematically generate such a context from a formal specification of a C function. this is applied to a subset of the ACSL specification language in order to generate suitable contexts for the abstract interpretation-based value analysis plug-ins of Frama-C, a framework for analysis of code written in C. the idea here presented has been implemented in a new Frama-C plug-in which is currently in use in an operational industrial setting.

关键词： Formal specification Code generation transformation Code analysis Frama-C ACSL

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Functional and Constraint logic programming 1

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丛书名： Lecture Notes in Computer Science

1000年

作者： Herbert Kuchen

ISBN: (数字)9783642225314

ISBN: (纸本)9783642225307

this book constitutes the refereed conference proceedings of the 20th international Workshop on Functional and Constraint logic programming, WFLP 2011, held in Odense, Denmark, in July 2011 as Part of the 13th international symposium on Principles and Practice of Declarative programming (PPDP 2011), the 22st international symposium on logic-based program synthesis and transformation (LOPSTR 2011), and the 4th international Workshop on Approaches and Applications of Inductive programming (AAIP 2011). From the 10 papers submitted, 9 were accepted for presentation the proceeding. the papers cover current research in all areas of functional and logic programming as well as the integration of constraint logic and object-oriented programming, and term rewriting.

关键词： logics and Meanings of programs Mathematical logic and Formal Languages programming Languages, Compilers, Interpreters Artificial Intelligence Symbolic and Algebraic Manipulation Computer Imaging, Vision, Pattern Recognition and Graphics

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