Fig. 13
From: Hierarchical multi step Gray Wolf optimization algorithm for energy systems optimization

Objective function of each algorithm with a centroid value of 6.43768 8 (a), and the probability of objective function of 11.90%, 30.95%, 50%, 69.04%, and 88.09% (b) for GWO, MGWO, MMSCC-GWO, CCS-GWO, and HMS-GWO respectively.