2015 Volume 19 Issue 6 Pages 227-234
The quantum-inspired evolutionary algorithm (QEA) and QEA with a pair-swap strategy (QEAPS), where each gene is represented by a quantum bit (qubit) in both algorithms, have shown superior search performance to the classical genetic algorithm in the 0-1 knapsack problem. Also, from experimental results for the integer knapsack problem, a novel integer-type gene-coding method that can obtain an integer value as an observation result by assigning multiple qubits in a gene locus has shown superior search performance to the conventional binary-type gene-coding method. However, the integer-type gene-coding method cannot deal with permutations simply. Therefore, we have proposed two interpretation methods that can deal with permutations in order to expand the gene-coding method based on the qubit representation. From the results of a computer experiment using the proposed interpretation methods in the traveling salesman problem, we have clarified that the two proposed interpretation methods can search for the optimal solution, even with the gene-coding method based on the qubit representation. Moreover, there are suitable rotation angles for discovering the optimal solution that depend on the algorithm.
