Figure 1

20-job, 2-process JSP instance considered in this work and its optimal solutions. Colors at the bottom of each box indicate whether early or late delivery costs apply for each time slot. Colors in the corners of each box indicate whether the production cost applies for each machine and consecutive time slot. By fixing some jobs to their optimal slots we generate instances with different numbers of free variables N. This is indicated by the background color/pattern of a box: grey for fixed slots and jobs, white for free slots and jobs, and dashes for free slots but fixed jobs. We generated instances with \(N=5, 10, 12, 16, 23\) free variables (see Table 1). The figure shows \(N=23\)