This function replaces the chromosomes based on rank and crowding distance. Initially until the population size is reached each front is added one by one until addition of a complete front which results in exceeding the population size. At this point the chromosomes in that front is added subsequently to the population based on crowding distance.
[N, m] = size(intermediate_chromosome); % Get the index for the population sort based on the rank [temp,index] = sort(intermediate_chromosome(:,M + V + 1)); clear temp m % Now sort the individuals based on the index for i = 1 : N sorted_chromosome(i,:) = intermediate_chromosome(index(i),:); end % Find the maximum rank in the current population max_rank = max(intermediate_chromosome(:,M + V + 1)); % Start adding each front based on rank and crowing distance until the % whole population is filled. previous_index = 0; for i = 1 : max_rank % Get the index for current rank i.e the last the last element in the % sorted_chromosome with rank i. current_index = max(find(sorted_chromosome(:,M + V + 1) == i)); % Check to see if the population is filled if all the individuals with % rank i is added to the population. if current_index > pop % If so then find the number of individuals with in with current % rank i. remaining = pop - previous_index; % Get information about the individuals in the current rank i. temp_pop = ... sorted_chromosome(previous_index + 1 : current_index, :); % Sort the individuals with rank i in the descending order based on % the crowding distance. [temp_sort,temp_sort_index] = ... sort(temp_pop(:, M + V + 2),'descend'); % Start filling individuals into the population in descending order % until the population is filled. for j = 1 : remaining f(previous_index + j,:) = temp_pop(temp_sort_index(j),:); end return; elseif current_index < pop % Add all the individuals with rank i into the population. f(previous_index + 1 : current_index, :) = ... sorted_chromosome(previous_index + 1 : current_index, :); else % Add all the individuals with rank i into the population. f(previous_index + 1 : current_index, :) = ... sorted_chromosome(previous_index + 1 : current_index, :); return; end % Get the index for the last added individual. previous_index = current_index; end