Solution Strategies for a Multiport Container Ship Stowage Problem

Table 4

Results obtained with the GRASP algorithm on both sets grouped by number of ports (N). Column # shows the number of instances tested in each group, column #Z shows the total number of solutions found with 0 reshuffles, and #Opt. shows the total number of optimal solutions. The average number of reshuffles and average time in seconds are expressed in columns Res. and CPU.

		GRASP
N	#	#Z	#Opt.	Res.	CPU
Set I
4	95	95	95	0.0	1.1
6	95	93	93	0.1	10.7
8	95	93	93	0.0	8.5
10	95	84	84	0.1	48.0
12	95	72	72	0.4	87.7
14	95	54	54	1.0	140.8
16	95	41	41	1.6	183.1
18	95	39	39	1.8	194.8
20	95	12	12	4.1	271.9
22	95	20	20	4.3	253.7
Total	950	603	603	1.3	120.0
Set II
4	120	116	117	0.1	0.0
6	120	88	89	0.7	4.5
8	120	70	74	1.3	32.3
10	120	31	33	3.1	115.7
12	120	14	14	5.0	168.1
14	120	14	15	7.6	193.1
16	120	6	9	11.6	217.1
Total	840	339	351	4.2	104.4