New Tabu Search Results for the Job Shop Scheduling Problem

In the classical job shop scheduling problem (JSSP), n jobs are processed to completion on m unrelated machines. Each job requires processing on each machine exactly once. For each job, technology constraints specify a complete, distinct routing which is fixed and known in advance. Processing times are sequence-independent, fixed, and known in advance. Each machine is continuously available from time zero, and operations are processed without preemption. The objective is to minimize the maximum completion time (makespan). This report describes a dynamic, adaptive tabu search (TS) strategy for JSSP incorporating elements of an earlier investigation by the authors. Improved computational results for a set of reference problems are presented. MS prepared April, 1994 Revised June, 1996