A Hybrid IP/GA Approach to the Parallel Production Lines Scheduling Problem

Table 2

Experimental result for the small sized problems.

Problem		Objective value		CPU time (seconds)
		MILP/CP	IP/GA	MILP/CP	IP/GA
1		56	56	3.41	<1
2		58	58	0.86	<1
3		61	61	1.14	1.13
4		79	79	14.87	1.21
5		81	81	3.48	1.79
6		67	67	143.34	2.76
7		94	94	23.55	4.84
8		87	87	6.56	4.16
9		67	67	31.42	2.89
10		53	53	39.38	4.54
11		102	102	207.51	5.30
12		113	113	71.35	6.13

The optimal solution is obtained but gap is not equal to 0.