Frédéric Gardi

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This paper introduces LocalSolver 1.x, a black-box local-search solver for general 0-1 programming. This software allows OR practitioners to focus on the modeling of the problem using a simple formalism, and then to defer its actual resolution to a solver based on efficient and reliable local-search techniques. Started in 2007, the goal of the LocalSolver(More)
In this paper, a real-life problem of task scheduling with human resource allocation is addressed. This problem was approached by the authors in the context of the ROADEF 2007 Challenge, which is an international competition organized by the French Operations Research Society. The subject of the contest, proposed by the telecommunications company France(More)
The NP-hard problem of car sequencing appears as the heart of the logistic process of many car manufacturers. The subject of the ROADEF’2005 Challenge addressed a car sequencing problem proposed by the car manufacturer RENAULT, more complex than the academic problem generally addressed in the literature. This paper describes two local search approaches for(More)
In this paper, a new practical solution approach based on randomized local search is presented for tackling a real-life inventory routing problem. Inventory routing refers to the optimization of transportation costs for the replenishment of customers’ inventories: based on consumption forecasts, the vendor organizes delivery routes. Our model takes into(More)
In this paper, the mutual exclusion scheduling problem is addressed. Given a simple and undirected graph G and an integer k, the problem is to find a minimum coloring of G such that each color is used at most k times. When restricted to interval graphs or related classes like circular-arc graphs and tolerance graphs, the problem has some applications in(More)
The NP-hard problem of car sequencing has received a lot of attention these last years. Whereas a direct approach based on integer programming or constraint programming is generally fruitless when the number of vehicles to sequence exceeds the hundred, several heuristics have shown their efficiency. In this paper, very large-scale neighborhood improvement(More)
This note summarizes the main results presented in the author’s Ph.D. thesis, supervised by Professor Michel Van Caneghem and defended on 14th June 2005 at University of Aix-Marseille II, France. The thesis, written in French, is available at Rapports/25-2005.html. The mutual exclusion scheduling problem has an elegant(More)
A methodology is presented for tackling mixed-integer nonlinear optimization problems by local search, in particular large-scale real-life problems. This methodology is illustrated through the localsearch heuristic implemented for solving an energy management problem posed by the EDF company in the context of the ROADEF/EURO Challenge 2010, an international(More)
In this paper, a real-life routing and scheduling problem encountered is addressed. The problem, which consists in optimizing the delivery of fluids by tank trucks on a long-term horizon, is a generalization of the vehicle routing problem with vendor managed inventory replenishment. The particularity of this problem is that the vendor monitors the(More)