XCSP3 is an XML-based format designed to represent instances of combinatorial constrained problems from the angle of Constraint Programming (CP). XCSP3 is an intermediate integrated format that can represent each instance separately while preserving its structure. Important:
- for only dealing with the most popular constraints and frameworks, use XCSP3-core;
- for modeling problems declaratively, and compiling them into XCSP3 instances, use the Python library PyCSP3.
Constraint Programming Format
Many supported frameworks: CSP, COP, WCSP, QCSP, DisCSP, ...
Many types of variables and constraints
Many variations of popular constraints
Reification and Relaxation
Natural mechanisms to keep structure:
- Arrays of variables
- Groups of constraints
- Blocks of constraints
Resources and Tools
More than 23,000 instances
Parsers developped in Java, C++ and Rust
PyCSP3: Python Library for modeling
- August 30, 2023
- 2023 XCSP3 Competition; held with CP 2023; see the results.
- December 15, 2021
- PySCP3 2.0 , Version 2 of the Python library PyCSP3.
- December 15, 2021
- ACE 2.0 , Version 2 of the generic constraint solver ACE (written in Java).
- January 16, 2021
- Specifications of XCSP3, Version 3.0.7
Here, we present two XCSP3 instances for two well-known problems:
<instance format="XCSP3" type="COP"> <variables> <array id="x" size=""> 0 1 </array> </variables> <constraints> <sum> <list> x </list> <coeffs> 11 24 5 23 16 </coeffs> <condition> (le,100) </condition> </sum> </constraints> <objectives> <maximize type="sum"> <list> x </list> <coeffs> 46 46 38 88 3 </coeffs> </maximize> </objectives> </instance>
All Interval problem
<instance format="XCSP3" type="CSP"> <variables> <array id="x" size="" note="x[i] is the ith value of the series"> 0..4 </array> <array id="y" size="" note="y[i] is the distance between x[i] and x[i+1]"> 1..4 </array> </variables> <constraints> <allDifferent> x </allDifferent> <allDifferent> y </allDifferent> <group class="channeling"> <intension> eq(%0,dist(%1,%2)) </intension> <args> y x x </args> <args> y x x </args> <args> y x x </args> <args> y x x </args> </group> </constraints> </instance>
Series of InstancesThis website contains many <a href=/series>series</a> of XCSP3 problem instances.
- A Java 8 Parser, a C++ 11 Parser, and a Rust parser are available
- A Java 8 Solution Checker is available
- A Python Library for modeling and compiling problems: PyCSP3
- A Java API for modeling and compiling problems: JvCSP3
- Many useful information about global constraints in the Global Constraint Catalog
- Many useful information about problems and models at CSPLib - a problem libary for constraints