arXiv AI

Counterfactual Routing Using Integer Programming with Constraint Generation

The paper "Counterfactual Routing Using Integer Programming with Constraint Generation" presents a solution to the IJCAI 2025 Counterfactual Routing Competition. The authors model the problem as an integer program and iteratively add constraints until an exact solution is found. In evaluation on held‑out test instances, their method ranked fourth in solution quality and was the fastest, averaging 9.0 seconds versus 118.8 seconds for the next‑fastest submission.

arXiv Machine Learning
Sep 7

GNN-Guided Graph Coarsening and Adaptive QUBO Penalties for the Capacitated Vehicle Routing Problem with Time Windows on a Quantum Annealer

The paper presents a method for reducing the size of Quadratic Unconstrained Binary Optimization (QUBO) models used to solve the Capacitated Vehicle Routing Problem with Time Windows (CVRPTW) on quantum annealers. It introduces adaptive penalty calibration to improve constraint satisfaction and replaces hand‑tuned merge heuristics with a graph neural network (GNN) that consistently achieves higher feasibility across Solomon benchmark families. Experiments on simulated annealing and a D‑Wave Advantage2 processor show significant reductions in constraint violations and improved feasibility rates, with the QUBO size remaining 5–6 times smaller.

By Youssef Kamel Rezk, Pawe{\l} Gora