Component Thermodynamical Selection Based Gene Expression Programming for Function Finding

Algorithm 4

Pseudocode of CTSGEP algorithm.

GEP Based on Component Thermodynamical Selection

 Step  1   Create a random initial population 𝑃₀;

 Step  2   Evaluate the population 𝑃₀, and calculate the absolute energy of each individual

according to (6);

 Step  3   𝑡=0, 𝑘=0, 𝑇=𝑇0;

 Step  4   Compute the absolute energy window 𝑊_𝑡 according to (7);

 Step  5   while (FES < MAX_FES)

      {

       for (𝑖=0; 𝑖<LK; 𝑖++)

       {

         Create M new individuals by the uniform selection, mutation,

      transposition-insertion and recombination operator;

        Establish the offspring population 𝑂_𝑡 by the M new individuals;

        Evaluate the population 𝑂_𝑡, and calculate the absolute energy of each

      individual according to (6);

        Save the best individual;

       Compute the absolute energy window 𝑊_𝑡+1 according to (8);

       Utilize CTS operator to select N individuals from 𝑃_𝑡∪𝑂_𝑡 for the next generation;

        𝑡=𝑡+1;

       }

      𝑘=𝑘+1;

      𝑇=𝑇0/(𝑘+1);

      }

 Step  6   Output the best individual.