www.pudn.com > NSGAII.rar > replace_chromosome.m, change:2008-11-26,size:1978b


rfunction f  = replace_chromosome(intermediate_chromosome,pro,pop) 
%% replace_chromosome(intermediate_chromosome,pro,pop) 
% 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,V] = size(intermediate_chromosome); 
switch pro 
        case 1 
        M = 2; 
        V = 6; 
    case 2 
        M = 3; 
        V = 12; 
end 
 
% Get the index for the population sort based on the rank 
[temp,index] = sort(intermediate_chromosome(:,M + V + 1)); 
 
% 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 
    current_index = max(find(sorted_chromosome(:,M + V + 1) == i)); 
    if current_index > pop 
        remaining = pop - previous_index; 
        temp_pop = ... 
            sorted_chromosome(previous_index + 1 : current_index, :); 
        [temp_sort,temp_sort_index] = ... 
            sort(temp_pop(:, M + V + 2),'descend'); 
        for j = 1 : remaining 
            f(previous_index + j,:) = temp_pop(temp_sort_index(j),:); 
        end 
        return; 
    elseif current_index < pop 
        f(previous_index + 1 : current_index, :) = ... 
            sorted_chromosome(previous_index + 1 : current_index, :); 
    else 
        f(previous_index + 1 : current_index, :) = ... 
            sorted_chromosome(previous_index + 1 : current_index, :); 
        return; 
    end 
    previous_index = current_index; 
end