Table 4: Evaluation indices results of fitting of different models.

GEP ANN Arps MEP
MSE 4.1131 8.4920 7.6548 3.2877
RMS 2.0281 2.9141 2.7667 1.8132
MRPE(%) 26.9855 49.3731 34.9134 30.6310
R 0.6607 0.3839 -0.4807 0.5893