XCSP3 is a universal format, based on XML, allowing to represent instances of constrained combinatorial problems. This format is compact, comprehensible and structured (it offers in particular the possibility to declare arrays of variables and identify syntactic and semantic groups of constraints).

XCSP3 introduces a limited set of elementary constraint forms, and allows many variations of them through different logical mechanisms. As a result, XCSP3 encompasses virtually all the constraints that can be found in different constraint solvers.

To deal only with the most popular constraints and frameworks, it is possible to focus on XCSP3-core. To model the problems in a declarative way and compile them as XCSP3 instances, it is possible to use the Python library PyCSP3.

You can consult the tools and the specifications of XCSP3.


Authors :
Gilles Audemard
Frédéric Boussemart
Christophe Lecoutre
Cédric Piette

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    Source code

    International journals

    2020 Constraints Gilles Audemard, Frédéric Boussemart, Christophe Lecoutre, Cédric Piette, Olivier Roussel, XCSP3 and its ecosystem in Constraints Journal (Constraints), pp. 1-23, 2020.

    Technical reports

    2022 Gilles Audemard, Christophe Lecoutre, Emmanuel Lonca, Proceedings of the 2022 XCSP3 Competition 2022.
    2021 Frederic Boussemart, Christophe Lecoutre, Gilles Audemard, Cédric Piette, XCSP3: An Integrated Format for Benchmarking Combinatorial Constrained Problems 2021.
    2021 Frédéric Boussemart, Christophe Lecoutre, Gilles Audemard, Cédric Piette, XCSP3-core: A Format for Representing Constraint Satisfaction/Optimization Problems 2021.