【指数Lyapunov】Lyapunov指数的MATLAB仿真

clc;
clear;
close all;
warning off;

n=10000;a=3:0.0001:4;  
%这里取了0.001，比原题的更精细
len=length(a);
a=reshape(a,len,1);
sum=zeros(len,1);
unit=ones(len,1);
x=unit*0.1;
for i=1:n  
    y=a.*(unit-2*x);  
    sum=sum+log(abs(y));   
    x=a.*x.*(unit-x);
end
lamuda=sum/5000;
    %根据评论修改过
    plot(a,lamuda)
    axis([3.6 4 -5 1])
    grid on 
    
    xlabel('u')
    ylabel('Lyapunov指数\lambda') 
    title('指数Lyapunov 指数的关系曲线')