Implementation of iterative local search (ILS) for the quadratic
assignment problem
Abstract
The quadratic assignment problem (QAP) is one of the hardest NPhard
problems and problems with a dimension of 20 or more can be difficult to
solve using exact methods. The QAP has a set of facilities and a set of
locations. The goal is to assign each facility to a location such that
the product of the flow between pairs of facilities and the distance
between them are minimized. Sometimes there is also a cost associated
with assigning a facility to a location. In this work, I solve the QAP
using a population based iterative local search with open source code in
C++. Results show that the code is able to solve all nug instances to
optimality, thereby proving that the algorithm is capable of solving
larger problems for which optimum solutions are not known.