SBPO 2025 Brazil

Events

Marion Technical Writer August 15, 2025

Hexaly is proud to be the Diamond Sponsor of SBPO 2025, held October 5-9, 2025, in Gramado, Brazil. The conference program can be accessed here.

Come by the Hexaly booth to meet Fred Gardi, Founder & CEO of Hexaly, and discover the new release Hexaly 14.0, which delivers dramatic performance improvements for solving Routing, Scheduling, Packing, Clustering, Assignment, Location, and many other problems in Supply Chain and Workforce Optimization. This is also the opportunity to explore and discuss our many job offers. Below are the abstracts of Fred’s talks at the 2025 SBPO conference in Gramado, Brazil:

Hexaly, a new kind of global optimization solver, by Fred Gardi, Ph.D.

06/10/2025 | Sala: Araucárias | Categoria: Palestra | 15:10 – 16:10

Hexaly is a new type of global optimization solver. Its modeling interface is nonlinear and set-oriented. It also supports user-coded functions, enabling seamless integration of simulation with optimization or machine learning with optimization. The Hexaly API unifies modeling concepts from mixed-integer programming, nonlinear programming, and constraint programming. Under the hood, Hexaly combines various exact and heuristic optimization methods: spatial branch-and-bound, simplex methods, interior-point methods, propagation, automatic branch-cut-price, local search, and surrogate modeling.

Hexaly stands out from traditional solvers like Gurobi, CPLEX, and OR-Tools by delivering super-fast solutions to problems such as routing, sequencing, scheduling, packing, clustering, matching, assignment, and location. For example, Hexaly provides solutions close to the best-known results in the literature for vehicle routing problems with thousands of points and scheduling problems with millions of tasks, achieving this in just one minute of runtime on a basic computer.

In addition to the Optimizer, Hexaly offers an innovative platform called Hexaly Studio, designed to prototype, develop, and deploy optimization applications quickly in a low-code fashion. This web-based platform is also well-suited for educational purposes; like all other Hexaly products, it is free for faculty and students.

Automatic column generation and elimination techniques inside Hexaly, by Fred Gardi, Ph.D.

Hexaly is a model-and-run solver that integrates heuristics and exact methods. A set and permutation-based modeling formalism was introduced to simplify the modeling of combinatorial problems, like routing, scheduling, or packing problems. For instance, in a routing problem, list variables can be used to model the sequence of visits made by each truck. These decision variables are suited for a heuristic search but are much more challenging to integrate into a mathematical programming approach to computing lower bounds. A direct reformulation in a MILP model introduces a quadratic number of binary decisions with several big M constraints, leading to poor scalability and bounds. Hexaly automatically detects such structures in a user model and reformulates them in an extended MILP model to compute lower bounds parallel to a heuristic search. This model is solved efficiently using state-of-the-art branch-and-cut-and-price techniques and column elimination algorithms. This talk will present the general approach, the algorithms used for the resolution, and some benchmarks on the classical vehicle routing and packing problems.

We look forward to connecting with the Brazilian Operations Research and Mathematical Optimization community at the 2025 SBPO in Brazil.