106 articles – 48 Notices  [english version]
HAL : hal-00421752, version 1

Fiche détaillée  Récupérer au format
Mathematical Programming, Series A 113, 2 (2008) 241-257
Projected Chvátal–Gomory cuts for mixed integer linear programs
Pierre Bonami 1, Gérard Cornuéjols 1, 2, Sanjeeb Dash 3, Matteo Fischetti 4, Andrea Lodi 5
(02/06/2008)

Recent experiments by Fischetti and Lodi show that the first Chvátal closure of a pure integer linear program (ILP) often gives a surprisingly tight approximation of the integer hull. They optimize over the first Chvátal closure by modeling the Chvátal–Gomory (CG) separation problem as a mixed integer linear program (MILP) which is then solved by a general- purpose MILP solver. Unfortunately, this approach does not extend immediately to the Gomory mixed integer (GMI) closure of an MILP, since the GMI separation problem involves the solution of a nonlinear mixed integer program or a parametric MILP. In this paper we introduce a projected version of the CG cuts, and study their practical effectiveness for MILP problems. The idea is to project first the linear programming relaxation of the MILP at hand onto the space of the integer variables, and then to derive Chvátal–Gomory cuts for the projected polyhedron. Though theoretically dominated by GMI cuts, projected CG cuts have the advantage of producing a separation model very similar to the one introduced by Fischetti and Lodi, which can typically be solved in a reasonable amount of computing time.
1 :  Laboratoire d'informatique Fondamentale de Marseille (LIF)
CNRS : UMR6166 – Université de la Méditerranée - Aix-Marseille II – Université de Provence - Aix-Marseille I
2 :  Tepper School of Business
Carnegie Mellon University
3 :  IBM Watson Research Center
IBM
4 :  Dipartimento di Ingegneria de l'Informazione [Padova] (DEI)
Università degli studi di Padova
5 :  Dipartimento di Elettronica, Informatica e Sistemistica (DEIS)
University of Bologna
Informatique/Recherche opérationnelle

Mathématiques/Optimisation et contrôle
Mixed integer linear program - Chvátal–Gomory cut - Separation problem - Projected polyhedron