selection.m

%轮盘赌选择操作
%pop_size: 种群大小
%chromo_size: 染色体长度
%cross_rate: 是否精英选择

function selection(pop_size, chromo_size, elitism)
global pop;
global fitness_table;

for i=1:pop_size
    r = rand * fitness_table(pop_size);
    first = 1;
    last = pop_size;
    mid = round((last+first)/2);
    idx = -1;
    while (first <= last) && (idx == -1) 
        if r > fitness_table(mid)
            first = mid;
        elseif r < fitness_table(mid)
            last = mid;     
        else
            idx = mid;
            break;
        end
        mid = round((last+first)/2);
        if (last - first) == 1
            idx = last;
            break;
        end
   end
   
%    for j=1:chromo_size
        pop_new(i,:)=pop(idx,:);
%    end
end
if elitism
    p = pop_size-1;
else
    p = pop_size;
end
% for i=1:p
%    for j=1:chromo_size
        pop(1:p,:) = pop_new(1:p,:);
%    end
% end

% clear i;
% clear j;
% clear pop_new;
% clear first;
% clear last;
% clear idx;
% clear mid;