Branch-and-cut and hybrid local search for themulti-level capacitated minimum spanning tree problem.

• Autor(a) principal: Uchoa, Eduardo
• Data de Publicação: 2012
• Outros Autores: Toffolo, Túlio Ângelo Machado, Souza, Maurício Cardoso de, Martins, Alexandre Xavier, Fukasawa, Ricardo
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFOP
• Texto Completo: http://www.repositorio.ufop.br/handle/123456789/7176; http://onlinelibrary.wiley.com/doi/10.1002/net.20485/epdf; https://doi.org/10.1002/net.20485
• topic: Network design; Fenchel cuts

We propose algorithms to compute tight lower boundsand high quality upper bounds (UBs) for the multilevelcapacitated minimum spanning tree problem. We firstdevelop a branch-and-cut algorithm, introducing somenew features: (i) the exact separation of cuts correspond-ing to some master equality polyhedra found in theformulation; (ii) the separation of Fenchel cuts, solvingLPs considering all the possible solutions restricted tosmall portions of the graph. We then use that branch-and-cut within a GRASP that performs moves by solvingto optimality subproblems corresponding to partial solu-tions. The computational experiments were conductedon 450 benchmark instances from the literature. Numer-ical results show improved best known (UBs) for almostall instances that could not be solved to optimality.