Automatic Generation of CHR Constraint Solvers

In this paper, we present a framework for automatic generation of CHR solvers given the logical specification of the constraints. This approach takes advantage of the power of tabled resolution for constraint logic programming, in order to check the validity of the rules. Compared to previous works where different methods for automatic generation of constraint solvers have been proposed, our approach enables the generation of more expressive rules (even recursive and splitting rules) that can be used directly as CHR solvers.Comment: to be published in Theory and Practice of Logic Programming, 16 pages, 2 figure

Box constraint collections for adhoc constraints.

Cheng Chi Kan.Thesis (M.Phil.)--Chinese University of Hong Kong, 2003.Includes bibliographical references (leaves 101-105).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 2 --- Background --- p.4Chapter 2.1 --- Propagation Based Constraint Solving --- p.4Chapter 2.1.1 --- "Valuations, Domains and Constraints" --- p.4Chapter 2.1.2 --- Solving a CSP --- p.6Chapter 2.1.3 --- Propagators --- p.7Chapter 2.1.4 --- Domain Consistency --- p.8Chapter 2.1.5 --- Bounds Consistency --- p.9Chapter 2.1.6 --- Propagation-based Backtracking Search --- p.10Chapter 2.2 --- Disjunction --- p.12Chapter 2.2.1 --- Speculative --- p.12Chapter 2.2.2 --- Cardinality --- p.12Chapter 2.2.3 --- Constructive Disjunction --- p.13Chapter 3 --- Box Constraint Collections --- p.15Chapter 3.1 --- Box Constraint Collections --- p.15Chapter 3.2 --- Separable Constraints --- p.17Chapter 4 --- Building Box Constraint Collections --- p.22Chapter 4.1 --- The bccFinder Algorithm --- p.22Chapter 4.2 --- Heuristics for the bccFinder Algorithm --- p.30Chapter 4.2.1 --- The Order of Box Expansion --- p.30Chapter 4.2.2 --- The Conditions of Box Expansion --- p.35Chapter 5 --- Compiling BCCs into Indexicals --- p.37Chapter 5.1 --- Indexicals --- p.37Chapter 5.2 --- Basic Compilation --- p.45Chapter 5.3 --- Optimizing Compilation --- p.49Chapter 5.3.1 --- Subsumption Indexicals --- p.49Chapter 5.3.2 --- Union Indexicals --- p.50Chapter 5.4 --- Hybrid Approach --- p.71Chapter 6 --- Experiments --- p.76Chapter 7 --- Related Work --- p.93Chapter 8 --- Concluding Remarks --- p.98Chapter 8.1 --- Contributions --- p.98Chapter 8.2 --- Future Work --- p.9

Towards Inductive Constraint Solving

A difficulty that arises frequently when writing a constraint solver is to determine the constraint propagation and simplification algorithm. In previous work, different methods for automatic generation of propagation rules [5,17,3] and simplification rules [4] for constraints defined over finite domains have been proposed. In this paper, we present a method for generating rule-based solvers for constraint predicates defined by means of a constraint logic program, even when the constraint domain is infinite. This approach can be seen as a concrete step towards Inductive Constraint Solving