SUMMARYWe consider the problem of minimizing the makespan on identical parallel machines subject to release dates and delivery times. The objective of this paper is to develop exact branch-and-bound algorithms to solve this strongly NP-hard problem. A preprocessing algorithm is devised to speed up the convergence of the proposed algorithms, and a new tight bounding scheme is introduced. The search tree is also reduced using a polynomial selection algorithm. Extensive computational experiments show that instances with up to 300 jobs can be solved exactly in a moderate CPU time.

We address the problem of minimizing makespan on identical parallel machines. We propose new lower bounding strategies and heuristics for this fundamental scheduling problem. The lower bounds are based on the so‐called lifting procedure. In addition, two optimization‐based heuristics are proposed. These heuristics require iteratively solving a subset‐sum problem. We present the results of computational experiments that provide strong evidence that the new proposed lower and upper bounds consistently outperform the best bounds from the literature.

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