OR 2026 Passau, Germany

Events

Marion Technical Writer July 30, 2026

Hexaly is proud to be a Gold Sponsor of OR 2026, the International Conference on Operations Research organized by the German Operations Research Society (GOR). The conference will take place from September 1 to 4, 2026, at the University of Passau, Germany. Join us throughout the event to discover the latest developments in optimization technology and connect with the Operations Research community.

Come visit the Hexaly booth at OR 2026 and meet our team throughout the conference. We will be happy to connect if you have questions, want to learn more about our next-generation optimization technology, or are curious about the latest features introduced in Hexaly 15.0. This release delivers major performance improvements in routing, scheduling, and packing, as well as significant advances in nonlinear optimization.

OR 2026 is also a great opportunity to:

• Discuss real-world optimization challenges
• Discover how leading companies use Hexaly
• Explore career opportunities within our team in an informal setting

Hexaly Talks at OR 2026 in Passau

Below are the abstracts of Hexaly’s talks at OR 2026.

Hexaly Workshop: modeling and solving routing problems with Hexaly Studio
Léa Blaise, Ph.D., Senior Optimization Scientist, Hexaly
Tuesday, September 1, 13:15 – 14:30, Room TBA

Hexaly Optimizer is a next-generation mathematical optimization solver that extends the traditional Mixed-Integer Programming (MIP) paradigm with a richer modeling framework. Alongside classical algebraic formulations, it supports native combinatorial constructs, nonlinear expressions, and black-box optimization, enabling users to express complex optimization problems in a compact and natural way. By preserving high-level problem structure, Hexaly automatically leverages advanced algorithmic techniques, including decomposition methods, column generation, branch-price-and-cut, and decision diagrams. As a result, it delivers state-of-the-art performance across challenging optimization domains such as routing, scheduling, packing, simulation-based optimization, machine-learning-driven decision problems, and more.

In this hands-on workshop, we will focus on the application of Hexaly to routing problems, showcasing how the solver’s set-based modeling capabilities naturally align with the structure of these problems. Participants will be guided through building and solving real-world routing problems using Hexaly Studio, a web-based integrated development environment designed specifically for optimization modeling. Hexaly Studio features intuitive dashboards, interactive widgets, and graphical solution visualizations, making it easy to both formulate models and interpret results. Through guided examples and interactive problem-solving, participants will gain hands-on experience with Hexaly and will be equipped to explore it further in their own research or applied projects.

Model representation and primal heuristics in Hexaly
Michael Feldmeier, Optimization Scientist, Hexaly
Wednesday, September 2, 16:30 – 18:00, Room HS6

Hexaly is a mathematical optimization solver based on various operations research techniques, combining both exact and approximate methods such as linear programming, non-linear programming, constrained programming and primal heuristics. Depending on the implementation of the solution technique, a different technical representation of the users model may be required. Among other variants, the model could be stored as an expression tree, or in the form of a collection of e.g. uni- bi- and multivariate functions. In the same manner, one algorithm can be implemented to work on several technical model variants. In this talk, we will highlight some of the features of the latest release of Hexaly, as well as present some model representations within Hexaly, and compare how some primal heuristics (such as Undercover) perform when implemented and run on those different models.

Solving continuous nonlinear problems with Hexaly
Nikolas Stott, Ph.D., Senior Optimization Scientist, Hexaly
Thursday, September 3, 8:30 – 10:00, Room HS6

Hexaly is a next-generation MIP solver combining many exact and heuristic operations research techniques. It offers a “model-and-run” approach to combinatorial, continuous or mixed optimization problems.

We present the techniques employed by the solver on continuous nonlinear problems. The problem can be provided as an expression graph, as pairs of opaque functions provided by the user to obtain the value and gradient of objectives and constraints, or a mix of both. When the model is provided as an expression graph, the solver can perform an analysis pass to identify the model’s structure such as linearity, quadratic convexity or general convexity. When the model contains opaque user functions, some structures become undetectable and the most general case is identified instead.

Hexaly leverages this information to choose the most efficient algorithms for a given model without any user input. When possible, Hexaly favors running an interior point method using explicit hessians. It falls back to a first order method (augmented lagrangian or quasi-newton interior point method) when hessian matrices are unavailable, e.g. due to memory constraints. All these algorithms are modular and their configurations can target a wide spectrum of problems: linear or nonlinear, convex or nonconvex, few or many constraints, dense or sparse, etc.

We compare the performance and robustness of Hexaly with Ipopt and SCIP. Three instance sets are used: portfolio optimization (convex QPs), pooling (nonconvex QCQPs) and general nonlinear instances exported from the CUTEst library.

What’s new in the Hexaly Optimizer 
Leona Gottwald, Senior Optimization Scientist, Hexaly
Wednesday, September 2, 10:30 – 12:00, Room HS6

We will look at recent advancements in the Hexaly Optimizer with a particular focus on the solvers behavior on the class of mixed integer programming (MIP) problems.  This includes algorithmic advancements, such as in presolve and cutting plane separation, as well as technical improvements that affect the solver performance.  Where available computational results are presented that highlight the impact of the changes. 

We look forward to connecting with the Operations Research community at the 2026 OR conference in Passau, Germany.

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