Programming constraint services

This thesis presents design, application, implementation, and evaluation of computation spaces as abstractions for programming constraint services at a high level. Spaces are seamlessly integrated into a concurrent programming language and make constraintbased computations compatible with concurrency through encapsulation. Spaces are applied to search and combinators as essential constraint services. State-of-the-art and new search engines such as visual interactive search and parallel search are covered. Search is expressive and concurrency-compatible by using copying rather than trailing. Search is space and time efficient by using recomputation. Composable combinators, also known as deep-guard combinators, stress the control facilities and concurrency integration of spaces. The implementation of spaces comes as an orthogonal extension to the implementation of the underlying programming language. The resulting implementation is shown to be competitive with existing constraint programming systems.Diese Dissertation beschreibt Entwurf, Verwendung, Implementierung und Evaluierung von Computation Spaces für die Programmierung von Constraintdiensten. Spaces werden in eine nebenläufige Programmiersprache integriert. Sie fungieren als Kapseln für Berechnungen mit Constraints. Dadurch wird die Kompatibilität zu nebenläufigen Berechnungen gewährleistet. Suche und Kombinatoren sind zentrale Constraintdienste, die mit Spaces programmiert werden. Es werden sowohl übliche, als auch vollkommen neue Suchmaschinen, wie zum Beispiel interaktive Suche und parallele Suche, vorgestellt. Durch Kopieren wird Suche ausdrucksstark und kompatibel mit Nebenläufigkeit. Durch Wiederberechnung wird Suche effizient hinsichtlich Speicherbedarf und Laufzeit. Kombinatoren, die ineinander geschachtelt werden können (so genannte deep-guard Kombinatoren), verdeutlichen die Kontrollmöglichkeiten von Spaces. Die Implementierung von Spaces erfolgt als orthogonale Erweiterung einer Implementierung für die zugrundeliegende Programmiersprache. Das Ergebnis ist konkurrenzfähig zu existierenden Constraintprogrammiersystemen

A toolkit for constraint-based inference engines

10.1007/3-540-46584-7_132ND International Workshop on Practical Aspects of Declarative Languages (PADL2000)1753185-199Boston, M

A Toolkit for Constraint-based Inference Engines

Solutions to combinatorial search problems can benefit from custommade constraint-based inference engines that go beyond depth-first search. The concurrent constraint language Oz provides support for programming inference engines. The Mozart system for Oz comes with several engines, extended in dimensions such as interaction, visualization, and optimization. However, these extensions are monolithic in their software design, not catering for systematic reuse of components. We present an object-oriented modular architecture for building inference engines that achieves high reusability and supports rapid prototyping of search algorithms and their extensions. The SearchToolKit, a public domain search library for Oz based on the presented architecture, provides evidence for the practicality of the design. 1 Introduction Finite domain constraint programming (CP(FD)) grew out of research in logic programming. Almost all programming systems for CP(FD) are based on Prolog, including libraries ..

A Toolkit for Constraint-based Inference Engines

Solutions to combinatorial search problems can benefit from custom-made constraint-based inference engines that go beyond depthfirst search. Several constraint programming systems support the programming of such inference engines through programming abstractions. For example, the Mozart system for Oz comes with several engines, extended in dimensions such as interaction, visualization, and optimization. However, so far such extensions are monolithic in their software design, not catering for systematic reuse of components. We present an object-oriented modular architecture for building inference engines that achieves high reusability and supports rapid prototyping of search algorithms and their extensions. For the sake of clarity, we present the architecture in the setting of a C++ constraint programming library. The SearchToolKit, a search library for Oz based on the presented architecture, provides evidence for the practicality of the design