A Mixed Integer Linear Formulation and a Grouping League Championship Algorithm for a Multiperiod-Multitrip Order Picking System with Product Replenishment to Minimize Total Tardiness

Table 7

Results on instances with 100 orders.

Instance	Periods	No. of picker	Capacity level	Optimal/best solution		GPSO				GLCA				GAP (%)
				Objective function	Time (s)	Objective function			Average times (s)	Objective function			Average times (s)
						Min	Avg.	Max		Min	Avg.	Max
109	3	3	1		1500	92	92	92	38.7	92	92	92	41.3	0
110			2		1500	92	93.5	95	70.2	92	92	92	70.7	1.6
111			3		1500	53	65.25	75	150.2	46	47.5	48	142.3	37.4
112		5	1		1500	95	95	95	75.6	95	95	95	71.5	0
113			2		1500	40	44	48	103.2	40	40	40	96.6	10
114			3		1500	76	81	85	327.3	65	67.75	69	330.5	19.6
115		7	1		1500	95	95	95	75	95	95	95	71.8	0
116			2		1500	74	76.75	79	248.5	74	74	74	217.5	3.7
117			3		1500	43	46.25	50	298.8	37	37	37	283.8	25
118	5	3	1		1500	190	190	190	64.5	190	190	190	56.2	0
119			2		1500	94	99.5	104	161	92	92	92	173.8	8.2
120			3		1500	141	163	170	302.4	139	139.25	140	312.4	17.1
121		5	1		1500	200	200	200	147.9	200	200	200	130.7	0
122			2		1500	123	129.25	136	238.4	120	120	120	259.9	7.7
123			3		1500	72	81.25	93	456.2	65	65.5	67	412.9	24
124		7	1		1500	190	190	190	199.8	190	190	190	171.8	0
125			2		1500	77	80.75	83	344.8	74	74	74	341.2	9.1
126			3		1500	46	49.25	52	452.3	37	37	37	497.5	33.1
127	7	3	1		1500	285	285	285	132.1	285	285	285	131.8	0
128			2		1500	234	253	273	199.7	230	230	230	188	10
129			3		1500	162	175	180	332.9	138	138	138	323.2	26.8
130		5	1		1500	285	285	285	158.6	285	285	285	141	0
131			2		1500	121	129	138	401.7	120	120	120	408	7.5
132			3		1500	75	81.5	90	469.7	65	65	65	395.6	25.4
133		7	1		1500	190	190	190	287.1	190	190	190	244.5	0
134			2		1500	75	82	86	651.7	74	74	74	550	10.8
135			3		1500	37	45.5	52	825	37	37	37	757.2	23
Avg.														11.11

no feasible solution found.