Local Optima Networks of the Quadratic Assignment Problem

Using a recently proposed model for combinatorial landscapes, Local Optima Networks (LON), we conduct a thorough analysis of two types of instances of the Quadratic Assignment Problem (QAP). This network model is a reduction of the landscape in which the nodes correspond to the local optima, and the edges account for the notion of adjacency between their basins of attraction. The model was inspired by the notion of `inherent network' of potential energy surfaces proposed in physical-chemistry. The local optima networks extracted from the so called uniform and real-like QAP instances, show features clearly distinguishing these two types of instances. Apart from a clear confirmation that the search difficulty increases with the problem dimension, the analysis provides new confirming evidence explaining why the real-like instances are easier to solve exactly using heuristic search, while the uniform instances are easier to solve approximately. Although the local optima network model ...

• Type: Conference
• Year: 2010
• Where: CEC
• Authors: Fabio Daolio, Sébastien Vérel, Gabriela Ochoa, Marco Tomassini
• Keywords: Artificial Intelligence, CEC 2010, Combinatorial Landscapes, Local Optima, Local Optima Network