Revisiting a Cornuéjols-Nemhauser-Wolsey formulation for the p-median problem

We revisit a formulation for the simple plant facility location and p-median problems introduced by Cornuéjols, Nemhauser and Wolsey (1980). Despite being the smallest known formulation regarding the number of variables, this formulation is barely used or cited in the literature. Here, we reintroduc...

Full description

Saved in:
Bibliographic Details
Main Authors: Agostinho Agra, Cristina Requejo
Format: Article
Language:English
Published: Elsevier 2024-01-01
Series:EURO Journal on Computational Optimization
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2192440623000254
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1846123417797918720
author Agostinho Agra
Cristina Requejo
author_facet Agostinho Agra
Cristina Requejo
author_sort Agostinho Agra
collection DOAJ
description We revisit a formulation for the simple plant facility location and p-median problems introduced by Cornuéjols, Nemhauser and Wolsey (1980). Despite being the smallest known formulation regarding the number of variables, this formulation is barely used or cited in the literature. Here, we reintroduce the formulation for the p-median problem from a different perspective, resulting from the intersection of a selection problem with an additional family of optimality constraints to define the costs correctly. An alternative proof that the linear relaxation of the formulation is equivalent to the linear relaxation of the well-known classical formulation is provided. By exploring the optimality constraints we discuss approaches to derive bounds for large-size instances. These approaches are based on relaxations obtained by eliminating optimality constraints and can be seen as a simple matheuristic to solve large size instances. In particular, we characterize relaxations which provide the optimal solution, and therefore, can be seen as new formulations for the p-median problem. Computational tests are reported showing that the renewed formulation can be used efficiently to solve p-median instances.
format Article
id doaj-art-6507ded25e514dc592932cc7cf443a7f
institution Kabale University
issn 2192-4406
language English
publishDate 2024-01-01
publisher Elsevier
record_format Article
series EURO Journal on Computational Optimization
spelling doaj-art-6507ded25e514dc592932cc7cf443a7f2024-12-14T06:30:51ZengElsevierEURO Journal on Computational Optimization2192-44062024-01-0112100081Revisiting a Cornuéjols-Nemhauser-Wolsey formulation for the p-median problemAgostinho Agra0Cristina Requejo1Departamento de Matemática, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; Centro de Investigação e Desenvolvimento em Matemática e Aplicações (CIDMA), Portugal; Corresponding author.Lisbon School of Economics & Management, Universidade de Lisboa, Rua do Quelhas, 6, 1200-781 Lisboa, Portugal; Centro de Investigação e Desenvolvimento em Matemática e Aplicações (CIDMA), PortugalWe revisit a formulation for the simple plant facility location and p-median problems introduced by Cornuéjols, Nemhauser and Wolsey (1980). Despite being the smallest known formulation regarding the number of variables, this formulation is barely used or cited in the literature. Here, we reintroduce the formulation for the p-median problem from a different perspective, resulting from the intersection of a selection problem with an additional family of optimality constraints to define the costs correctly. An alternative proof that the linear relaxation of the formulation is equivalent to the linear relaxation of the well-known classical formulation is provided. By exploring the optimality constraints we discuss approaches to derive bounds for large-size instances. These approaches are based on relaxations obtained by eliminating optimality constraints and can be seen as a simple matheuristic to solve large size instances. In particular, we characterize relaxations which provide the optimal solution, and therefore, can be seen as new formulations for the p-median problem. Computational tests are reported showing that the renewed formulation can be used efficiently to solve p-median instances.http://www.sciencedirect.com/science/article/pii/S2192440623000254Locationp-medianSimple plant facility locationMixed integer formulation
spellingShingle Agostinho Agra
Cristina Requejo
Revisiting a Cornuéjols-Nemhauser-Wolsey formulation for the p-median problem
EURO Journal on Computational Optimization
Location
p-median
Simple plant facility location
Mixed integer formulation
title Revisiting a Cornuéjols-Nemhauser-Wolsey formulation for the p-median problem
title_full Revisiting a Cornuéjols-Nemhauser-Wolsey formulation for the p-median problem
title_fullStr Revisiting a Cornuéjols-Nemhauser-Wolsey formulation for the p-median problem
title_full_unstemmed Revisiting a Cornuéjols-Nemhauser-Wolsey formulation for the p-median problem
title_short Revisiting a Cornuéjols-Nemhauser-Wolsey formulation for the p-median problem
title_sort revisiting a cornuejols nemhauser wolsey formulation for the p median problem
topic Location
p-median
Simple plant facility location
Mixed integer formulation
url http://www.sciencedirect.com/science/article/pii/S2192440623000254
work_keys_str_mv AT agostinhoagra revisitingacornuejolsnemhauserwolseyformulationforthepmedianproblem
AT cristinarequejo revisitingacornuejolsnemhauserwolseyformulationforthepmedianproblem