Constraint Programming for Sustainable Development (CP4SD)
ACP Summer School 2025
Republic of Benin, Africa August 25 To 29, 2025
Starting in :
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Our speakers
Attempted Schedule
Monday, Aug 25, 2025
Tuesday, Aug 26, 2025
Wednesday, Aug 27, 2025
Thursday, Aug 28, 2025
Friday, Aug 29, 2025
09:00 - 10:30
Invited talk
Fundamentals of Optimization and Introduction to Constraint Programming
Hélène Verhaeghe
Hélène Verhaeghe
25/08/2025
IFRI Lab Room
Fundamentals of Optimization and Introduction to Constraint Programming
This session will cover the fundamentals of optimization and introduce constraint programming.
Optimization is the selection of a best element (with regard to some criteria) from some set of available alternatives.
Constraint programming is a programming paradigm where relations between variables are stated in the form of constraints.
Support, Consistency, and Global Constraints: Key Components of Constraint Propagation - Part 1
Roger Kameugne
Roger Kameugne
26/08/2025
IFRI Lab Room
Support, Consistency, and Global Constraints: Key Components of Constraint Propagation - Part 1
This talk highlights the pivotal role of constraint propagation in solving Constraint Satisfaction Problems (CSPs) within the field of constraint programming (CP). It begins by introducing the concept of support, a fundamental element underpinning the propagation process. This leads naturally to the notion of consistency, with particular emphasis on arc consistency(AC), the most commonly applied form. The discussion then turns to the concept of fixed points, which play a key role in CSP solving frameworks. The presentation underscores the benefits of using global constraints over their decomposition into simpler constraints, illustrated through the well-known example of the all-different constraint. The second part of the talk explores specific global constraints, such as disjunctive and cumulative constraints in scheduling, as well as element and circuit constraints, relevant to the Traveling Salesman Problem (TSP) and Vehicle Routing Problems (VRP). For each global constraint, a possible decomposition is presented, along with typical propagation rules, supported by illustrative examples.
Support, Consistency, and Global Constraints: Key Components of Constraint Propagation - Part 2
Roger Kameugne
Roger Kameugne
26/08/2025
IFRI Lab Room
Support, Consistency, and Global Constraints: Key Components of Constraint Propagation - Part 2
This talk highlights the pivotal role of constraint propagation in solving Constraint Satisfaction Problems (CSPs) within the field of constraint programming (CP). It begins by introducing the concept of support, a fundamental element underpinning the propagation process. This leads naturally to the notion of consistency, with particular emphasis on arc consistency(AC), the most commonly applied form. The discussion then turns to the concept of fixed points, which play a key role in CSP solving frameworks. The presentation underscores the benefits of using global constraints over their decomposition into simpler constraints, illustrated through the well-known example of the all-different constraint. The second part of the talk explores specific global constraints, such as disjunctive and cumulative constraints in scheduling, as well as element and circuit constraints, relevant to the Traveling Salesman Problem (TSP) and Vehicle Routing Problems (VRP). For each global constraint, a possible decomposition is presented, along with typical propagation rules, supported by illustrative examples.
This lab session will explain how solvers work in constraint programming. It also go through a the use of global constraints and how to implement a small one.
Search in focus: The Yang to Modeling's Yin in Constraint Programming - Part 1
Pierre Schaus
Pierre Schaus
27/08/2025
IFRI Lab Room
Search in focus: The Yang to Modeling's Yin in Constraint Programming
In this lecture, I’ll explain the crucial role of search strategies in Constraint Programming (CP). We start with the 'first fail' principle, a fundamental search strategy in CP. Our focus then shifts to expert-designed search strategies, particularly in complex areas like scheduling and vehicle routing, highlighting their practical applications. We'll discuss strategies to accelerate searches, including dominance and symmetry breaking, essential for speeding-up the search process. The lecture progresses to advanced successful black box search methods like conflict-based, activity-based, impact-based, and weighted degree approaches, all derivatives of the first fail principle. We then cover restart-based methods addressing the heavy-tail phenomenon in CP searches and Large Neighborhood Search (LNS) for quickly finding high-quality solutions. Finally, we touch on search parallelization, exploring how multiple processors can be utilized for more efficient problem-solving in CP.
Search in focus: The Yang to Modeling's Yin in Constraint Programming - Part 2
Pierre Schaus
Pierre Schaus
27/08/2025
IFRI Lab Room
Search in focus: The Yang to Modeling's Yin in Constraint Programming - Part 2
In this lecture, I’ll explain the crucial role of search strategies in Constraint Programming (CP). We start with the 'first fail' principle, a fundamental search strategy in CP. Our focus then shifts to expert-designed search strategies, particularly in complex areas like scheduling and vehicle routing, highlighting their practical applications. We'll discuss strategies to accelerate searches, including dominance and symmetry breaking, essential for speeding-up the search process. The lecture progresses to advanced successful black box search methods like conflict-based, activity-based, impact-based, and weighted degree approaches, all derivatives of the first fail principle. We then cover restart-based methods addressing the heavy-tail phenomenon in CP searches and Large Neighborhood Search (LNS) for quickly finding high-quality solutions. Finally, we touch on search parallelization, exploring how multiple processors can be utilized for more efficient problem-solving in CP.
