Algorithm 1 GWO pseudo-code

1: Initialize the grey wolf population $X_i\left(i=1,2,\dots ,n\right)$; 2: Initialize $a$, $A$, and $C$; 3: Calculate the fitness value for each grey wolf; 4: ${\overrightarrow{X}}_{\alpha }^0=$ the initial position of the leader wolf; 5: ${\overrightarrow{X}}_{\beta }^0=$ the initial position of the second-best wolf; 6: ${\overrightarrow{X}}_{\delta }^0=$ the initial position of the third-best wolf; 7: Calculate the initial position of prey (${\overrightarrow{X}}_P^0$) according to Equation (5); 8: While (t $<$ Max number of iterations) 9: For each grey wolf 10: Update the position of current grey wolf by Equation (1); 11: end For 12: Update $a$, $A$, and $C$; 13: Calculate the fitness value for each grey wolf; 14: Update ${\overrightarrow{X}}_{\alpha }^t$, ${\overrightarrow{X}}_{\beta }^t$, and ${\overrightarrow{X}}_{\delta }^t$; 15: Calculate the position of prey (${\overrightarrow{X}}_P^t$) according to Equation (5); 16: $t=t+1$; 17: End while 18: return ${\overrightarrow{X}}_{\alpha }^t$.