A Hybrid Multiobjective Evolutionary Approach for Flexible Job-Shop Scheduling Problems

Algorithm 2

Procedure of crossover for assignment.

Crossover

Select randomly two parents 𝑃₁ and 𝑃₂;

Select randomly two integers 𝑖 and 𝑖^′ such that 𝑖≤𝑖^′≤𝑁;

Select randomly two integers 𝑗 and 𝑗^′ such that 𝑗≤𝑛_𝑖 and 𝑗^′≤𝑛_𝑖′ (in the

case where 𝑖=𝑖^′,𝑗≤𝑗^′);

Child 𝐶₁ receives the same assignments from the parent 𝑃₁ for all opera-

tions between the operations 𝑂_𝑖𝑗 and 𝑂_{𝑖′𝑗′};

The rest of assignments for 𝐶₁ is obtained from 𝑃₂;

The construction of child 𝐶₂ is similar with 𝐶₁.