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16
Two Classes of Boolean Functions for Dependency Analysis
 SCIENCE OF COMPUTER PROGRAMMING
, 1994
"... Many static analyses for declarative programming/database languages use Boolean functions to express dependencies among variables or argument positions. Examples include groundness analysis, arguably the most important analysis for logic programs, finiteness analysis and functional dependency analys ..."
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Cited by 65 (4 self)
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Many static analyses for declarative programming/database languages use Boolean functions to express dependencies among variables or argument positions. Examples include groundness analysis, arguably the most important analysis for logic programs, finiteness analysis and functional dependency analysis for databases. We identify two classes of Boolean functions that have been used: positive and definite functions, and we systematically investigate these classes and their efficient implementation for dependency analyses. On the theoretical side we provide syntactic characterizations and study the expressiveness and algebraic properties of the classes. In particular, we show that both are closed under existential quantification. On the practical side we investigate various representations for the classes based on reduced ordered binary decision diagrams (ROBDDs), disjunctive normal form, conjunctive normal form, Blake canonical form, dual Blake canonical form, and two forms specific to de...
Generalized Semantics and Abstract Interpretation for Constraint Logic Programs
, 1995
"... We present a simple and powerful generalized algebraic semantics for constraint logic programs that is parameterized with respect to the underlying constraint system. The idea is to abstract away from standard semantic objects by focusing on the general properties of any possibly nonstandard ..."
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Cited by 38 (5 self)
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We present a simple and powerful generalized algebraic semantics for constraint logic programs that is parameterized with respect to the underlying constraint system. The idea is to abstract away from standard semantic objects by focusing on the general properties of any possibly nonstandard  semantic definition. In constraint logic programming, this corresponds to a suitable definition of the constraint system supporting the semantic definition. An algebraic structure is introduced to formalize the notion of a constraint system, thus making classical mathematical results applicable. Both topdown and bottomup semantics are considered. Nonstandard semantics for constraint logic programs can then be formally specified using the same techniques used to define standard semantics. Different nonstandard semantics for constraint logic languages can be specified in this ...
On the Complexity of Dataflow Analysis of Logic Programs
, 1992
"... This article reports some results on this correlation in the context of logic programs. A formal notion of the "precision" of an analysis algorithm is proposed, and this is used to characterize the worstcase computational complexity of a number of dataflow analyses with different degrees of precisi ..."
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Cited by 35 (4 self)
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This article reports some results on this correlation in the context of logic programs. A formal notion of the "precision" of an analysis algorithm is proposed, and this is used to characterize the worstcase computational complexity of a number of dataflow analyses with different degrees of precision. While this article considers the analysis of logic programs, the technique proposed, namely the use of "exactness sets" to study relationships between complexity and precision of analyses, is not specific to logic programming in any way, and is equally applicable to flow analyses of other language families.
Unfold/fold transformations of CCP programs
 ACM Transactions on Programming Languages and Systems
, 1998
"... We introduce a transformation system for concurrent constraint programming (CCP). We define suitable applicability conditions for the transformations which guarantee that the input/output CCP semantics is preserved also when distinguishing deadlocked computations from successful ones and when consid ..."
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Cited by 19 (5 self)
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We introduce a transformation system for concurrent constraint programming (CCP). We define suitable applicability conditions for the transformations which guarantee that the input/output CCP semantics is preserved also when distinguishing deadlocked computations from successful ones and when considering intermediate results of (possibly) nonterminating computations. The system allows us to optimize CCP programs while preserving their intended meaning: In addition to the usual benefits that one has for sequential declarative languages, the transformation of concurrent programs can also lead to the elimination of communication channels and of synchronization points, to the transformation of nondeterministic computations into deterministic ones, and to the crucial saving of computational space. Furthermore, since the transformation system preserves the deadlock behavior of programs, it can be used for proving deadlock freeness of a given program with respect to a class of queries. To this aim it is sometimes sufficient to apply our transformations and to specialize the resulting program with respect to the given queries in such a way that the obtained program is trivially deadlock free.
Abstracting Synchronization in Concurrent Constraint Programming
 In Proc. 5th Int'l Symposium on Programming Language Implementation and Logic Programming
, 1994
"... ing Synchronization in Concurrent Constraint Programming ? Enea Zaffanella 1 Roberto Giacobazzi 2 Giorgio Levi 1 1 Dipartimento di Informatica, Universit`a di Pisa Corso Italia 40, 56125 Pisa (zaffanel,levi)@di.unipi.it 2 LIX, Laboratoire d'Informatique, ' Ecole Polytechnique 91128 Palaisea ..."
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Cited by 13 (5 self)
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ing Synchronization in Concurrent Constraint Programming ? Enea Zaffanella 1 Roberto Giacobazzi 2 Giorgio Levi 1 1 Dipartimento di Informatica, Universit`a di Pisa Corso Italia 40, 56125 Pisa (zaffanel,levi)@di.unipi.it 2 LIX, Laboratoire d'Informatique, ' Ecole Polytechnique 91128 Palaiseau cedex giaco@lix.polytechnique.fr Abstract. Because of synchronization based on blocking ask, some of the most important techniques for data flow analysis of (sequential) constraint logic programs (clp) are no longer applicable to cc languages. In particular, the generalized approach to the semantics, intended to factorize the (standard) semantics so as to make explicit the domaindependent features (i.e. operators and semantic objects which may be influenced by abstraction) becomes useless for relevant applications. A possible solution to this problem is based on a more abstract (nonstandard) semantics: the success semantics, which models non suspended computations only. With a program tr...
Using Narrowing Approximations to Optimize Equational Logic Programs
 IN PROC. OF PLILP’93
, 1993
"... Solving equations in equational theories is a relevant programming paradigm which integrates logic and equational programming into one unified framework. Efficient methods based on narrowing strategies to solve systems of equations have been devised. In this paper, we formulate a narrowingbased ..."
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Cited by 12 (6 self)
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Solving equations in equational theories is a relevant programming paradigm which integrates logic and equational programming into one unified framework. Efficient methods based on narrowing strategies to solve systems of equations have been devised. In this paper, we formulate a narrowingbased equation solving calculus which makes use of a topdown abstract interpretation strategy to control the branching of the search tree. We define
A Transformation System for CLP with Dynamic Scheduling and ccp
 In Proc. of the ACM Sigplan PEPM’97
, 1997
"... In this paper we study unfold/fold transformations for constraint logic programs (CLP) with dynamic scheduling and for concurrent constraint programming (ccp). We define suitable applicability conditions for this transformations which ensure us that the original and the transformed program have the ..."
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Cited by 11 (2 self)
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In this paper we study unfold/fold transformations for constraint logic programs (CLP) with dynamic scheduling and for concurrent constraint programming (ccp). We define suitable applicability conditions for this transformations which ensure us that the original and the transformed program have the same results of successful computations and have the same deadlocked derivations. The possible applications of these results are twofold. On one hand we can use the unfold/fold system to optimize CLP and ccp programs while preserving their intended meaning and in particular without the risk of introducing deadlocks. On the other hand, unfold/fold transformations can be used for proving deadlock freedom for a class of queries in a given program: to this aim it is sufficient to specialize the program with respect to the given queries in such a way that the resulting program is trivially deadlock free. As shown by several interesting examples, this yields a methodology for proving deadlock free...
Layered Modes
, 1999
"... Modes were introduced in logic programming to differentiate the input arguments of a predicate from its output arguments. This information can be used for verifying the most diverse properties of logic programs, notably absence of runtime errors and absence of deadlocks in presence of delay declara ..."
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Cited by 9 (3 self)
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Modes were introduced in logic programming to differentiate the input arguments of a predicate from its output arguments. This information can be used for verifying the most diverse properties of logic programs, notably absence of runtime errors and absence of deadlocks in presence of delay declarations. We introduce here layered modes, an extension of existing mode systems which allow us to enlarge the class of programs which can be verified by using modes. In particular, we show that this extension allows us to better handle programs that employ a dynamic selection rule and programs that use incomplete data structures such as differencelists.
Efficient Analysis of Logic Programs with Dynamic Scheduling
 Proc. Twelfth International Logic Programming Symposium
, 1995
"... The first logic programming languages, such as Prolog, used a fixed lefttoright atom scheduling rule. Recent logic programming languages, however, usually provide more flexible scheduling in which computation generally proceeds lefttoright but in which some calls are dynamically "delayed" until ..."
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Cited by 8 (1 self)
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The first logic programming languages, such as Prolog, used a fixed lefttoright atom scheduling rule. Recent logic programming languages, however, usually provide more flexible scheduling in which computation generally proceeds lefttoright but in which some calls are dynamically "delayed" until their arguments are sufficiently instantiated to allow the call to run efficiently. Such languages include constraint logic programming languages in which constraints which are "too hard" are delayed and concurrent constraint languages in which delay on shared variables is used to provide asynchronous communication between processes. We give a new framework for the global analysis of logic programming languages with dynamic scheduling which is based on approximating the delayed atoms by a closure operator. We give an example analysis for groundness based on this framework, and give the results of an implementation which demonstrates the method is practical. 1 Introduction The first logic pr...
A Compositional Semantic Basis for the Analysis of Equational Horn Programs
, 1996
"... Keywords: Mar'ia Alpuente Moreno Falaschi Germ'an Vidal September 4, 1996 A Compositional Semantic Basis for the Analysis of Equational Horn Programs This work has been partially supported by CICYT under grant TIC 950433C0303 and by HCM project CONSOLE. Departamento de Sistemas Inform'aticos y ..."
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Cited by 7 (5 self)
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Keywords: Mar'ia Alpuente Moreno Falaschi Germ'an Vidal September 4, 1996 A Compositional Semantic Basis for the Analysis of Equational Horn Programs This work has been partially supported by CICYT under grant TIC 950433C0303 and by HCM project CONSOLE. Departamento de Sistemas Inform'aticos y Computaci'on, Universidad Polit'ecnica de Valencia, Camino de Vera s/n, Apdo. 22012, 46071 Valencia, Spain. e.mail: alpuente,gvidal @dsic.upv.es Dipartimento di Matematica e Informatica, Universit`a di Udine, Via delle Scienze 206, 33100 Udine, Italy. e.mail: falaschi@dimi.uniud.it We introduce a compositional characterization of the operational semantics of equational Horn programs. Then we show that this semantics and the standard operational semantics based on (basic) narrowing coincide. We define an abstract narrower mimicking this semantics, and show how it can be used as a basis for efficient ANDcompositional program analysis. As an application of our framework, we show a composition...