A Modified Social Spider Optimization for Economic Dispatch with Valve-Point Effects

Algorithm 1

Pseudocode of the subpopulation dynamically updating strategy.

(1)	for each subpopulation SPi belonging to male subpopulation or female subpopulation
(2)	for each individual in SPi
(3)	Calculate for each according to the opposite of equation (1).
(4)	Calculate for each according to the opposite of equation (1), where is the best individual.
(5)	end for Si
(6)	Calculate for SPi according to equation (17).
(7)	end for SPi
(8)	Determine the updated subpopulation denoted as based on the small . Another one denoted as . Then, all the spiders in in descending order of the fitness and the top 20% of spiders are selected to form a set of candidate migrator .
(9)	for each individual in
(10)	Calculate for each according to the opposite of equation (1), where is the best individual.
(11)	end for Si
(12)	Select the spider with the largest , which is used to replace the spider with the worst fitness in . Meanwhile, is replaced by new spider randomly generated in .