A Hybrid Genetic Algorithm to Minimize Total Tardiness for Unrelated Parallel Machine Scheduling with Precedence Constraints

Table 7

Comparison between HGA and CGA for large-sized instances with different density of precedence constraints (𝐷).

𝑛=60		𝑓HGA	𝑓CGA	Mean CPU time (s)	Δ𝑓GA (%)
𝑚=10
𝜌=0.5
RD=0.1
𝑝𝑗𝑣∼DU[1,10]
𝐷	0.2	100.8	364.0	183.2	72.3
	0.4	135.5	481.1	182.8	71.8
	0.6	375.5	935.6	183.2	59.9
	0.8	782.0	1733.3	184.3	54.9