Machine Learning for/with Mixed-Integer Optimization

Ph.D. level course exploring the intersection of Machine Learning and Mixed-Integer Optimization, covering how MIO enhances ML and how ML improves MIO solvers.

Course Description

The course covers recent results on combining the strengths of Machine Learning (ML)/ Artificial Intelligence (AI) and Mixed-Integer Optimization (MIO) technologies. It discusses how MIO can be used to enhance AI methods in settings with scarce and unreliable data, in high-stakes situations where interpretability and fairness play fundamental roles, and when tackling engineering problems requiring human-AI collaborations.

The course also explores how AI can be used to improve solving MIO problems, using it to learn ML-based alternatives to key heuristic components of MIO solvers such as branching, understand the key structural properties of a given instance, learn effective configurations of MIO solvers and predict the performance of a given algorithm, thus improving decision-making throughout the solution process.

Learning Objectives

After completing this course, students will be able to:

  1. Formulate and solve AI/ML problems using MIO technology.
  2. Apply different ML techniques in the context of mixed-integer optimization.
  3. Read and write a paper at the intersection of AI/ML and MIO.

Weekly Topics and Readings

Week 7.1: MIO for Robustness and Outliers

  • Bertsimas et al. “Robust classification.” INFORMS Journal on Optimization (2019).
  • Gómez, A. “Outlier detection in time series via mixed-integer conic quadratic optimization.” SIAM Journal on Optimization (2021).
  • Insolia et al. “Simultaneous feature selection and outlier detection with optimality guarantees.” Biometrics (2022).

Week 7.2: MIO for Graphical Models

  • Gómez et al. “Real time solution of quadratic optimization problems with banded matrices and indicator variables.” Operations Research (2025).
  • Liu et al. “A graph-based decomposition method for convex quadratic optimization with indicators.” Mathematical Programming (2022).

Week 9: MIP Algorithm Configuration and Runtime Prediction

  • Hutter et al. “ParamILS: an automatic algorithm configuration framework.” Journal of Artificial Intelligence Research (2009).
  • Lawless et al. “LLMs for cold-start cutting plane separator configuration.” CPAIOR (2025).

Week 10: ML for MIP Branching

  • Khalil et al. “Learning to branch in mixed integer programming.” AAAI (2016).
  • Gasse et al. “Exact Combinatorial Optimization with Graph Convolutional Neural Networks.” NeurIPS (2019).
  • Cai et al. “Learning backdoors for mixed integer programs with contrastive learning.” ECAI (2024).

Week 11: ML for MIP Meta-heuristics

  • Sonnerat et al. “Learning a large neighborhood search algorithm for mixed integer programs.” arXiv (2021).
  • Huang et al. “Searching large neighborhoods for integer linear programs with contrastive learning.” ICML (2023).
  • Huang et al. “Contrastive predict-and-search for mixed integer linear programs.” ICML (2024).

Week 12: MIO for Artificial Neural Networks

  • Anderson et al. “Strong mixed-integer programming formulations for trained neural networks.” Mathematical Programming (2020).
  • Tjandraatmadja et al. “The convex relaxation barrier, revisited: Tightened single-neuron relaxations for neural network verification.” NeurIPS (2020).

Week 13: ML for MIP Branch-and-Bound: Beyond Branching

  • Khalil et al. “Learning to run heuristics in tree search.” IJCAI (2017).
  • Paulus et al. “Learning to cut by looking ahead: Cutting plane selection via imitation learning.” ICML (2022).
  • Labassi et al. “Learning to compare nodes in branch and bound with graph neural networks.” NeurIPS (2024).

Week 14: ML for Combinatorial Optimization

  • Dai et al. “Learning combinatorial optimization algorithms over graphs.” NeurIPS (2017).
  • Cappart et al. “Combinatorial Optimization and Reasoning with Graph Neural Networks.” JMLR (2023).
  • Sun and Yang. “Difusco: Graph-based diffusion solvers for combinatorial optimization.” NeurIPS (2023).

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