Table 1. GP parameters and operators used for the seven combinations of objectives (Co1 to Co7).

GP configuration
Number of runs	5
Number of topics	25
Number of generations	150
Number of subpopulations	1
Population size	100
Crossover probability, cxPb	0.7
Mutation probability, mutPb	0.3
Initial tree depth	1–5
Maximum crossover depth	17
Parent selection operator	selDoubleTournament