Hybrid Differential Evolution with Biogeography-Based Optimization for Design of a Reconfigurable Antenna Array with Discrete Phase Shifters

Algorithm 6

Procedure Algorithm description of DE/BBO algorithm

Begin

Step  1: Set the generation counter G=0; and randomly initialize a population of NP individuals 𝑋_𝑖. Initialize the parameter 𝐹, CR

Step  2: Evaluate the fitness for each individual in 𝑃

Step  3: while stopping criteria is not satisfied do

   For each individual calculate species count probability

   Calculate the immigration rate 𝜆_𝑖 and the emigration rate 𝜇_𝑘 for each individual

   for  𝑖=1 to NP

       select randomly 𝑎≠𝑏≠𝑐≠𝑑≠𝑖

     𝑗_rand=⌊rand(0,1)^∗𝐷⌋

    for  𝑗=1 to D

     if rand(0,1)< 𝜆_𝑖 then

     if rand(0,1)≤CR or 𝑗=𝑗_rand then

     𝑢_𝑖,𝑗=𝑥_𝑎,𝑗+𝐹×(𝑥_𝑏,𝑗−𝑥_𝑐,𝑗)

      else

      Select 𝑥_𝑘 with probability based on 𝜇_𝑘

     𝑢_𝑖,𝑗=𝑥_𝑘,𝑗

     end if

     else

     𝑢_𝑖,𝑗=𝑥_𝑖,𝑗

      end if

    end for

   end for

    for 𝑖=1 to NP do

     Evaluate the offspring 𝑢_𝑖

     If 𝑢_𝑖 is better than 𝑃_𝑖 then

      𝑃_𝑖=𝑢_𝑖

     end if

    end for

      Memorize the best solution achieved so far

Step  4: end while

End