Handling sequential ordering problem with quantum-inspired evolutionary algorithm

In this paper, QEA-SOP, a novel evolutionary algorithm inspired by quantum, is presented to handle the sequential ordering problem (SOP) which is well known as a classical NP-Hard combinatorial problem. In QEA-SOP, special individual representations and measure operator, inspired by some concepts and principles of quantum computing such as qubits and superposition of states, are introduced too. The measure algorithm with spreading and restraining principles projects the quantum chromosomes onto the matrix represented chromosomes quickly as well as satisfies the precedence constraints. And a so-called pattern matrix is also introduced to reflect the given precedence constraints. The experimental results show that the proposed algorithm can match the best known solution with a small number of initial individuals, a short span of time and a great diversity.