A PSO-Based Hybrid Metaheuristic for Permutation Flowshop Scheduling Problems

Table 4

Performance comparison of PSO_VNS and PSO* for total flowtime criterion.

Problem	PSOVNS		PSO*
	RPD	CPU (s)	RPD	CPU (s)
20×5	−0.175	3.18	−0.168	8.11
20×10	−0.037	7.21	−0.035	4.86
20×20	2.758	11.93	−0.068	24.97
50×5	−0.603	41.71	−0.531	40.28
50×10	−0.819	74.49	−0.892	44.32
50×20	0.857	143.32	−0.543	50.67
100×5	−0.570	222.28	−0.546	409.75
100×10	−0.692	407.88	−0.636	414.14
100×20	−0.104	824.41	−0.801	442.37
Average	0.068	192.93	−0.469	159.941

The bold font is used to highlight the better solutions.
*used to denote our algorithm.