In the no-idle flowshop, machines cannot be idle after finishing one job and before starting the next one.
Therefore, start times of jobs must be delayed to guarantee this constraint. In practice machines show
this behavior as it might be technically unfeasible or uneconomical to stop a machine in between jobs.
This has important ramifications in the modern industry including fiber glass processing, foundries,
production of integrated circuits and the steel making industry, among others. However, to assume that
all machines in the shop have this no-idle constraint is not realistic. To the best of our knowledge, this is
the first paper to study the mixed no-idle extension where only some machines have the no-idle
constraint. We present a mixed integer programming model for this new problem and the equations to
calculate the makespan. We also propose a set of formulas to accelerate the calculation of insertions that
is used both in heuristics as well as in the local search procedures. An effective iterated greedy (IG)
algorithm is proposed. We use an NEH-based heuristic to construct a high quality initial solution. A local
search using the proposed accelerations is employed to emphasize intensification and exploration in the
IG. A new destruction and construction procedure is also shown. To evaluate the proposed algorithm, we
present several adaptations of other well-known and recent metaheuristics for the problem and conduct
a comprehensive set of computational and statistical experiments with a total of 1750 instances.
The results show that the proposed IG algorithm outperforms existing methods in the no-idle and in the
mixed no-idle scenarios by a significant margin.Quan-Ke Pan is partially supported by the National Science Foundation of China 61174187, Program for New Century Excellent Talents in University (NCET-13-0106), Science Foundation of Liaoning Province in China (2013020016), Basic scientific research foundation of Northeast University under Grant N110208001, Starting foundation of Northeast University under Grant 29321006, and Shandong Province Key Laboratory of Intelligent Information Processing and Network Security (Liaocheng University). Ruben Ruiz is partially supported by the Spanish Ministry of Economy and Competitiveness, under the project "RESULT - Realistic Extended Scheduling Using Light Techniques" with reference DPI2012-36243-C02-01 co-financed by the European Union and FEDER funds and by the Universitat Politecnica de Valencia, for the project MRPIV with reference PAID/2012/202.Pan, Q.; Ruiz García, R. (2014). An effective iterated greedy algorithm for the mixed no-idle flowshop scheduling problem. Omega. 44:41-50. https://doi.org/10.1016/j.omega.2013.10.002S41504
