% 2.6 變異
% 變異(mutation)，基因的突變普遍存在于生物的進化過程中。變異是指父代中的每個個體的每一位都以概率 pm 翻轉，即由“1”變?yōu)椤?”，
% 或由“0”變?yōu)椤?”。遺傳算法的變異特性可以使求解過程隨機地搜索到解可能存在的整個空間，因此可以在一定程度上求得全局最優(yōu)解。
%遺傳算法子程序
%Name: mutation.m
%變異
function [newpop]=sga_mutation(popsize,chromlength,pop,pm)

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% popsize=10;
% pop=[1023,980,2133,726,1946,657,1702,1224,1522,807;
%      2025,2565,1773,2340,2354,1144,2061,240,1573,825]
% chromlength=12;
% pm=0.7;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


 pop1=pop(1,:);                %將種群矩陣拆分
 pop1;
 pop2=pop(2,:);
 pop2;
 
 pop1=dec2bin(pop1,chromlength);  %%各自轉為二進制
 pop1;
 pop2=dec2bin(pop2,chromlength);
 pop2;
 
newpop1=pop1;
newpop2=pop2;
for i=1:popsize;

   if(rand<pm) %產(chǎn)生一隨機數(shù)與變異概率比較
     mpoint=round(rand*chromlength);
%      mpoint
     if mpoint<=0
        mpoint=1;
     end

    if newpop1(i,mpoint)=='0'
       newpop1(i,mpoint)='1';
    else
       newpop1(i,mpoint)='0';
    end
   end  
   
    if(rand<pm) %產(chǎn)生一隨機數(shù)與變異概率比較
     mpoint=round(rand*chromlength);
%      mpoint
     if mpoint<=0
        mpoint=1;
     end  
     
     if newpop2(i,mpoint)=='0'
        newpop2(i,mpoint)='1';
     else
        newpop2(i,mpoint)='0';
     end
    end

end

newpop1=bin2dec(newpop1);
newpop2=bin2dec(newpop2);



for i=1:popsize
    if newpop1(i)>=12000
%         pop_init=randperm(20000); 
%         newpop1(i)=newpop1(i)-3095;  
        newpop1(i)=rand;
    end
    
    if newpop2(i)>=12000
%         newpop2(i)=newpop2(i)-3095;       
%         pop_init=randperm(20000); 
        newpop2(i)=rand;       
    end
    
end

newpop(1,:)=newpop1';
newpop(2,:)=newpop2';
newpop;