Finite domain constraint programming systems

Tutorial at CP'2002, Principles and Practice of Constraint Programming. Powerpoint slides.</p

Interactively solving school timetabling problems using extensions of constraint programming

Timetabling problems have been frequently studied due to their wide range of applications. However, they are often solved manually because of the lack of appropriate computer tools. Although many approaches mainly based on local search or constraint programming seem to have been quite successful in recent years, they are often highly dedicated to specific problems and encounter difficulties to take the dynamic and over-constrained nature of such problems. We were confronted with such an over-constrained and dynamic problem in our institution. This paper deals with a timetabling system based on constraint programming with the use of explanations to offer a dynamic behaviour and to allow automatic relaxations of constraints. Our tool has successfully answered the needs of the current planner by providing solutions in a few minutes instead of a week of manual design.We present in this paper the techniques used, the results obtained and a discussion on the effects of the automation of the timetabling process

Global Constraint Catalog, 2nd Edition

This report presents a catalogue of global constraints where each constraint is explicitly described in terms of graph properties and/or automata and/or first order logical formulae with arithmetic. When available, it also presents some typical usage as well as some pointers to existing filtering algorithms

Global Constraint Catalog, 2nd Edition (revision a)

This report presents a catalogue of global constraints where each constraint is explicitly described in terms of graph properties and/or automata and/or first order logical formulae with arithmetic. When available, it also presents some typical usage as well as some pointers to existing filtering algorithms

Challenging explanations for global constraints

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Explanations for Global Constraints: Instrumenting the Stretch Constraint

This article presents an extension of the stretch constraint for explanationbased solvers and algorithms. This extension implies the computation of precise explanations in order to justify all the decisions the filtering algorithm makes: value removals, domain reductions or contradiction. Experiments show a distinct improvement when using explanations to improve search

1 Département Informatique de l’École des Mines de Nantes

Abstract. This article presents the challenge of implementing explanations within global constraints. After defining explanations, it introduces what explanations for global constraints could be through the example of the all different constraint, then it presents the issues of their implementation and the interest of precise explanations. At last, it illustrates these principles with the stretch and flow constraints.