ACE (AbsCon Essence) is an open-source constraint solver developed by Christophe Lecoutre (CRIL) in Java.

Current stable version of ACE is 2.0 (December 15, 2021).

ACE focuses on:

• integer variables, including 0/1 (Boolean) variables,
• state-of-the-art table constraints, including ordinary, starred, and hybrid table constraints,
• popular global constraints (AllDifferent, Count, Element, Cardinality, Cumulative, etc.),
• search heuristics (wdeg, impact, last-conflict, BIVS, solution-saving, ...),
• mono-criterion optimization

ACE is distributed under License MIT

Quick Description

For some general information about the structure of the code of the solver ACE, see this short guide.

Building a JAR

1. clone the repository:
   git clone https://github.com/xcsp3team/ace.git
2. change directory:
   cd ace
3. run Gradle (of course, you need Gradle to be installed; version > v7.0):
   gradle build -x test
4. test the JAR:
   java -jar build/libs/ACE-YY-MM.jar
   where you give the right values for YY and MM. If the usage of ACE is displayed, you are fine.

With this JAR, you can run ACE on any XCSP3 instance.

Running Unit Tests

1. run Gradle:
   gradle test
2. see results in:
   ace/build/reports/tests/index.html