Table 5 Summary of parameters used in GEP models.

P1

Fitness Function

RMSE

RSE

P2

Function set

+, -, ×, /, Exp, Sin, Cos, Asin

+, -, ×, /, Inv, X², X³

P3

Chromosomes

30

30

P4

Head size

8

6

P5

Number of genes

4

5

P6

Linking function

Addition

Addition

P7

Mutation rate

0.0667

0.0769

P8

Inversion rate

0.1

0.1

P9

One-point recombination rate

0.2

0.1

P10

Two-point recombination rate

0.2

0.2

P11

Gene recombination rate

0.3

0.4

P12

Gene transposition rate

0.1

0.1

P13

Constant per gene

10

10

P14

Training-R²

0.331

0.572

P15

Testing-R²

0.393

0.522