no code implementations • 22 Aug 2024 • Swann Bessa, Darius Dabert, Max Bourgeat, Louis-Martin Rousseau, Quentin Cappart
Lagrangian decomposition (LD) is a relaxation method that provides a dual bound for constrained optimization problems by decomposing them into more manageable sub-problems.
no code implementations • 22 Dec 2023 • Augustin Parjadis, Quentin Cappart, Bistra Dilkina, Aaron Ferber, Louis-Martin Rousseau
Lagrangian relaxation is a versatile mathematical technique employed to relax constraints in an optimization problem, enabling the generation of dual bounds to prove the optimality of feasible solutions and the design of efficient propagators in constraint programming (such as the weighted circuit constraint).
1 code implementation • 5 Jan 2023 • Tom Marty, Tristan François, Pierre Tessier, Louis Gauthier, Louis-Martin Rousseau, Quentin Cappart
Important design choices in a solver are the branching heuristics, which are designed to lead the search to the best solutions in a minimum amount of time.
no code implementations • 16 Dec 2021 • Tu-San Pham, Antoine Legrain, Patrick De Causmaecker, Louis-Martin Rousseau
When our prediction-based approach is compared to flat-reservation policies, it does a better job of preventing overdue treatments for emergency patients, while also maintaining comparable waiting times for the other patients.
1 code implementation • 18 Feb 2021 • Félix Chalumeau, Ilan Coulon, Quentin Cappart, Louis-Martin Rousseau
This paper presents the proof of concept for SeaPearl, a new CP solver implemented in Julia, that supports machine learning routines in order to learn branching decisions using reinforcement learning.
no code implementations • 3 Feb 2021 • Léa Ricard, Guy Desaulniers, Andrea Lodi, Louis-Martin Rousseau
Two types of probabilistic models, namely similarity-based density estimation models and a smoothed Logistic Regression for probabilistic classification model, are compared on a dataset of more than 41, 000 trips and 50 bus routes of the city of Montr\'eal.
4 code implementations • 12 Jun 2020 • Chaitanya K. Joshi, Quentin Cappart, Louis-Martin Rousseau, Thomas Laurent
End-to-end training of neural network solvers for graph combinatorial optimization problems such as the Travelling Salesperson Problem (TSP) have seen a surge of interest recently, but remain intractable and inefficient beyond graphs with few hundreds of nodes.
1 code implementation • 2 Jun 2020 • Quentin Cappart, Thierry Moisan, Louis-Martin Rousseau, Isabeau Prémont-Schwarz, Andre Cire
In this work, we propose a general and hybrid approach, based on DRL and CP, for solving combinatorial optimization problems.
no code implementations • 18 Oct 2019 • Minh Hoàng Hà, Tat Dat Nguyen, Thinh Nguyen Duy, Hoang Giang Pham, Thuy Do, Louis-Martin Rousseau
We consider a vehicle routing problem which seeks to minimize cost subject to time window and synchronization constraints.
1 code implementation • 28 Sep 2019 • Antoine François, Quentin Cappart, Louis-Martin Rousseau
In this paper, we address the limitations of ML approaches for solving the TSP and investigate two fundamental questions: (1) how can we measure the level of accuracy of the pure ML component of such methods; and (2) what is the impact of a search procedure plugged inside a ML model on the performances?
1 code implementation • 10 Sep 2018 • Quentin Cappart, Emmanuel Goutierre, David Bergman, Louis-Martin Rousseau
Finding tight bounds on the optimal solution is a critical element of practical solution methods for discrete optimization problems.