Hexaly for Scheduling, by Philippe Laborie

Tutorial Scheduling

Louisa Technical Writer October 23, 2024

Philippe Laborie, Ph.D., Senior Optimization Scientist at Hexaly, was invited by Professor Zdeněk Hanzálek from the Czech Technical University in Prague to talk about “Hexaly for Scheduling” at the Scheduling Seminar on November 20, 2024. The webinar will focus on using Hexaly to model and solve complex industrial scheduling problems using Hexaly’s innovative modeling formalism.

The Scheduling Seminar is a platform where experts in optimization and scheduling share insights and advancements in solving real-world problems. Philippe shares his expertise in the field and demonstrates how Hexaly tackles a wide range of industrial optimization challenges, particularly in Supply Chain and Workforce Management. You will find the summary of his talk below.

Hexaly for Scheduling

Hexaly is a model-and-run mathematical optimization solver that addresses various industrial optimization problems in Supply Chain and Workforce Management, such as Routing, Scheduling, Packing, Clustering, Matching, Assignment, or Facility Location. Its mathematical formalism extends classical Mixed-Integer Linear Programming with set, permutation, and interval variables on which any usual algebraic operator (arithmetic, logic, relational, etc.) can be applied. Hexaly is widely used in industry today, has performances often comparable to the best dedicated algorithms, allows compact modeling, scales well (with problem size and complexity), and is constantly improving. This seminar focuses on using Hexaly to model and solve industrial scheduling problems. We show how to exploit the mathematical concepts of Hexaly’s formalism to model several classic scheduling problems elegantly and compactly and give an idea of the solver’s performance compared to the state of the art. Next, we outline the many techniques employed under the hood to produce good-quality primal and dual solutions like constraint propagation, local search, large neighborhood search, linear relaxations, scheduling heuristics, or exact scheduling algorithms on particular subproblems.

The replay of Philippe Laborie’s webinar, Hexaly for Scheduling, is available below.