分布估计算法之PBIL算法

%%%%%%%%%%%%PBIL algorithm
clc
clear
clf
tic           %%%%%%%%%%%开始计时
%%%%%%%%%%%%参数设置
Pop_Size=40;
Individual_Len=20;%%%%%%%%%每个变量的长度
Variable_Num=2;
Learning_Rate=0.01;
Iteration_Times=50;
I=1;
%%%%%%%%%%%%%%%产生初始种群
Binary_X=zeros（Pop_SizeVariable_NumIndividual_Len）;
for i=1:1:Pop_Size
    for j=1:1:Variable_Num
        for k=1:1:Individual_Len
            Binary_X（ijk）=round（rand（））;
        end
    end
end
Best_Individual=zeros（1Iteration_Times）;
Probability_Vector=zeros（Iteration_TimesVariable_NumIndividual_Len）;
traces=zeros（3Iteration_Times）;%%%%%追踪每一代的最优值
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%对每一代执行如下操作
while I<=Iteration_Times    
 %%%%%%%%%%%%%%%%将采样的值，由二进制转化到十进制
  Decimal_X=zeros（Pop_SizeVariable_Num）;
    for i=1:1:Pop_Size
        for j=1:1:Variable_Num  
            k=Individual_Len;
            t=1;
            while k>=1
               Decimal_X（ij）=Decimal_X（ij）+Binary_X（ijk）*2^（t-1）;
               k=k-1;
               t=t+1;
            end
        end
    end
    %%%%%%%%%%%%%%%%%将十进制映射到解空间中
    Solution=zeros（Pop_SizeVariable_Num）;
    for i=1:1:Pop_Size
        for j=1:1:Variable_Num
            Solution（ij）=-2+Decimal_X（ij）*4/（2^Individual_Len-1）;
        end
    end
    %%%%%%%%%%%%%%%%%%计算适应值
    Fitness_Value=zeros（1Pop_Size）;
    for i=1:1:Pop_Size
      %  Fitness_Value（i）=100*（Solution（i1）^2-Solution（i2））^2+（1-Solution（i1））^2;
    %  Fitness_Value（i）=Solution（i1）*cos（2*pi*Solution（i2））+Solution（i2）*sin（2*pi*Solution（i1））;
    %Fitness_Value（i）=Solution（i1）+Solution（i2）;
   % Fitness_Value（i）=Solution（i1）^2+Solution（i2）;
   %Fitness_Value（i）=Solution（i1）*Solution（i2）;
   %Fitness_Value（i）=（Solution（i1）-Solution（i2））^2;
    Fitness_Value（i）=Solution（i1）.*cos（2*pi*Solution（i2））+Solution（i2）.*cos（2*pi*Solution（i1））;
    end
    %%%%%%%%%%%%%%%%%%将适应值按照从小到大的顺序排序，并选出最优个体
    [FitnessValueindex]=sort（Fitness_Value）;%%%%%%%排序  
    Best_Individual（I）=Fitness_Value（index（Pop_Size））;%%%%%%%%选最优个体
    traces（1I）=Solution（index（Pop_Size）1）;
    traces（2I）=Solution（index（P