Discrete harmony search algorithm for identical parallel machine scheduling problem

Harmony search (HS) is a recently proposed meta-heuristic, which has gained much attention and some applications during the past decades. In this paper, a discrete HS (DHS) algorithm is proposed for solving identical parallel machines scheduling problem with the objective of minimizing makespan criterion. In the DHS method, a permutation-based encoding method and a new improvisation scheme is proposed to enable the continuous HS algorithm to be applied to solve combinatorial optimization problems. In addition, an efficient local search method is embedded in the DHS algorithm to enhance the accuracy and convergence rate of the proposed method. Numerical results and comparisons with other heuristics demonstrate that the proposed HS algorithm can effectively improve the searching quality.