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Beyond TamakiSato Style Unfold/Fold Transformations for Normal Logic Programs
 IN ASIAN, LNCS 1742
, 1999
"... Unfold/fold transformation systems for logic programs have been extensively investigated. Existing unfold/fold transformation systems for normal logic programs allow only TamakiSato style folding using clauses from a previous program in the transformation sequence: i.e., they fold using a singl ..."
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Unfold/fold transformation systems for logic programs have been extensively investigated. Existing unfold/fold transformation systems for normal logic programs allow only TamakiSato style folding using clauses from a previous program in the transformation sequence: i.e., they fold using a single, nonrecursive clause. In this paper we present a transformation system that permits folding in the presence of recursion, disjunction, as well as negation. We show that the transformations are correct with respect to various semantics of negation including the wellfounded model and stable model semantics.
Detecting Unsolvable Queries for Definite Logic Programs
, 1998
"... In logic programming, almost no work has been done so far on proving that certain queries cannot succeed. Work in this direction could be useful for queries which seem to be nonterminating. Such queries are not exceptional, e.g. in planning problems. The paper develops some methods, based on ab ..."
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In logic programming, almost no work has been done so far on proving that certain queries cannot succeed. Work in this direction could be useful for queries which seem to be nonterminating. Such queries are not exceptional, e.g. in planning problems. The paper develops some methods, based on abduction, goaldirectedness, tabulation, and constraint techniques, for proving failure of queries for definite logic programs. It also reports some experiments with various tools.
Partial Deduction System
 In Proc. of the ILPS'97 Workshop on Tools and Environments for (Constraint) Logic Programming, U.P
, 1997
"... We present the fully automatic partial deduction system ecce, which can be used to specialise and optimise logic programs. We describe the underlying principles of ecce and illustrate some of the potential application areas. Interesting possibilites of crossfertilisation with other fields such as r ..."
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We present the fully automatic partial deduction system ecce, which can be used to specialise and optimise logic programs. We describe the underlying principles of ecce and illustrate some of the potential application areas. Interesting possibilites of crossfertilisation with other fields such as reachability analysis of concurrent systems and inductive theorem proving are highlighted and substantiated. 1 Introduction Program specialisation, also called partial evaluation or partial deduction, is an automatic technique for program optimisation. The central idea is to specialise a given source program for a particular application domain. Program specialisation encompasses traditional compiler optimisation techniques, such as constant folding and inlining, but uses more aggressive transformations, yielding both the possibility of obtaining (much) greater speedups and more difficulty in controlling the transformation process. In addition to achieving important speedups, program special...
Some Achievements and Prospects in Partial Deduction
 Electronic Section)(3es):4
, 1998
"... Interpretation ". Danny De Schreye is Senior Research Associate of the Fund for Scientific Research  Flanders Belgium. Authors' addresses: M. Leuschel, B. Martens and D. De Schreye, Departement Computerwetenschappen, K.U.Leuven, Celestijnenlaan 200A, B3001 Heverlee, Belgium. Email : fmichael,b ..."
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Interpretation ". Danny De Schreye is Senior Research Associate of the Fund for Scientific Research  Flanders Belgium. Authors' addresses: M. Leuschel, B. Martens and D. De Schreye, Departement Computerwetenschappen, K.U.Leuven, Celestijnenlaan 200A, B3001 Heverlee, Belgium. Email : fmichael,bern,dannydg@cs.kuleuven.ac.be Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or direct commercial advantage and that copies show this notice on the first page or initial screen of a display along with the full citation. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, to redistribute to lists, or to use any component of this work in other works, requires prior specific permission and/or a fee. Permissions may be requested from Publicati...
Proofs by program transformations
 proceedings of Logicbased Program Synthesis and Transformation (LOPSTR
, 1999
"... ..."
Program Specialization via Algorithmic Unfold/Fold Transformations
 ACM Computing Surveys: Special Issue on Partial Evaluation
, 1998
"... this paper we will essentially refer to these techniques as they have been developed in the fields of functional and logic programming. ..."
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this paper we will essentially refer to these techniques as they have been developed in the fields of functional and logic programming.
Constrained partial deduction
 Proceedings of the 12th Workshop Logische Programmierung (WLP'97
, 1997
"... Partial deduction based upon the Lloyd and Shepherdson framework generates a specialised program given a set of atoms. Each such atom represents all its instances. This can severely limit the specialisation potential of partial deduction. We therefore extend the precision the Lloyd and Shepherdson a ..."
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Partial deduction based upon the Lloyd and Shepherdson framework generates a specialised program given a set of atoms. Each such atom represents all its instances. This can severely limit the specialisation potential of partial deduction. We therefore extend the precision the Lloyd and Shepherdson approach by integrating ideas from constraint logic programming. We formally prove correctness of this new framework of constrained partial deduction and illustrate its potential on some examples.
A Generalized Unfold/Fold Transformation System for Definite Logic Programs
, 1998
"... this paper. ..."
Making a Success out of Early Failures
, 1997
"... Promoting early failure of unsuccessful computations is a powerful optimization that enhances determinism in the evaluation of logic programs. This optimization has two principal components: 1) identifying and extracting conditions that yield information about the eventual success or failure of pred ..."
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Promoting early failure of unsuccessful computations is a powerful optimization that enhances determinism in the evaluation of logic programs. This optimization has two principal components: 1) identifying and extracting conditions that yield information about the eventual success or failure of predicates, 2) exploiting these conditions to avoid unnecessary computation. For the first part sophisticated compiletime global analysis methods exist that compute the necessary conditions for a predicate and its constituent clauses to succeed. In this paper we address the other problem, namely the exploitation of necessary conditions. Specifically we develop a technique for selecting tests from necessary conditions based on an analysis of their costs and benefits. The resulting optimized program does not create any more choice points or failure paths than the original program. More importantly, success path lengths in the optimized program can never grow any longer than the corresponding path...
Developing Correct and Efficient Logic Programs by Transformation
 Knowledge Engineering Review
, 1996
"... this paper, from formal specifications one may obtain executable, efficient programs by using techniques for transforming logic programs. This is, indeed, one of the reasons that makes logic programming very attractive for program construction. During this final step from specifications to programs, ..."
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this paper, from formal specifications one may obtain executable, efficient programs by using techniques for transforming logic programs. This is, indeed, one of the reasons that makes logic programming very attractive for program construction. During this final step from specifications to programs, in order to improve efficiency one may want to use program transformation for avoiding multiple visits of data structures, or replacing complex forms of recursion by tail recursion, or reducing nondeterminism of procedures. This paper is structured as follows. In Section 2 we present the rulebased approach to program transformation and its use for the derivation and synthesis of logic programs from specifications. In Section 3 we consider the schemabased transformation technique for the development of efficient programs. In Section 4 we consider the partial evaluation technique and its use for the specialization of logic programs when the input data are partially known at compile time. In the final section we discuss some of the achievements and challanges of program transformation as a tool for logicbased software engineering. For simplicity reasons in this paper we will only consider definite logic programs, although most of the techniques we will describe can be applied also in the case of general logic programs. We refer to [35, 41] for all notions concerning logic programming and logic program transformation which are not explicitly presented here.