function  muta=mutate(mclone)
    muta=mclone;
    r=zeros(1,12);
    ra=ceil(12*rand);
    r(ra)=1/sqrt(12);
             
    if ra>=1&ra<=3
        muta(1:3)=muta(1:3)-muta(1:3);                 
    elseif ra>=4&ra<=7
        muta(4:7)=muta(4:7)-muta(4:7);
    elseif ra==8
        muta(8)=muta(8)-muta(8);
    else
        muta(9:12)=muta(9:12)-muta(9:12);
    end                     
    muta(1:12)=muta(1:12)+r;        
    rstyle=rand(1,3)<1/12;
    muta(13:15)=muta(13:15)+rstyle;
    rstyle=muta(13:15)>1;
    muta(13:15)=muta(13:15)-2*rstyle;