Algorithm 1: Framework of the SSA
Input:  Tmax: the maximum iterations; PD: the number of producers; SD: the number of sparrows who perceive the danger; R2: the alarm value; N: total number of sparrows
Output:  Xbest: the current global optimal location; fg: fitness (Xbest)
while (t < Tmax)
	Rank the fitness values and find the current best individual and the current worst individual. R2 = rand (1)  # Update the alarm value randomly
	for $i=1:PD$  Using Equation (8), update the sparrow’s location end
	for $i=(PD+1):N$  Using Equation (9), update the sparrow’s location end
	for $i=1:SD$  Using Equation (10), update the sparrow’s location end for
	Get the current new location If the new location is better than before, update it t = t + 1
end while
Return Xbest, fg