Evolving a schedule with batching, precedence constraints, and sequence-dependent setup times: Crossover needs building blocks

Abstract

The Travelling Salesman Problem (TSP) has a “big valley” search space landscape: good solutions share common building blocks. In evolutionary computation, crossover mixes building blocks, and so crossover works well on TSP. This paper considers a more complicated and realistic single-machine problem, with batching/lotsizing, sequence dependent setup times, and time-dependent costs. Instead of a big valley, it turns out that good solutions share few building blocks. For large enough problems, good solutions have essentially nothing in common. This suggests that crossover (which mixes building blocks) is not suited to this more complex problem.