自治系統的Poincare截面的matlab程序實現
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% M File for systems, which can be modified by any autonomous chaotic systems, should be saved in the Work file of your Matlab!!!!!!!
function dx=Chu(t,x);
% Chu system [A new autonomous chaotic system, which has many similar properties and dissimilar properties with Lorenz families] 
% dx=Chu(t,[x;y;z;a;b;c])
% t-time，x,y,z- Parameters，a,b,c-coefficients
% eg: dx=Chu(0,[0.11;0.11;0.11;5;16;1])%Of course, you can verified the other values of parameter b if you like, 
%some typical are given in the listed paper below. 
%% Please refer one of our published papers as follows:
%褚衍東， 李險峰， 張建剛，常迎香.一個新自治混沌系統的計算機仿真與電路模擬. 
%《四川大學學報：自然科學版》-2007年44卷3期 -596-602.
dx(1,1)=x(4)*(x(2)-x(1));
dx(2,1)=x(1)*x(3)-x(2);
dx(3,1)=x(5)-x(1)*x(2)-x(6)*x(3);
dx(4,1)=0;
dx(5,1)=0;
dx(6,1)=0;


% Another M File, which can be pasted in the Command windows or saved in the Work file of your Matlab.

Z=[];
[T,Y]=ode45('Chu',[0,5000],[0.1;0.1;0.1;5;16;1]);
for k=1:length(Y) 
if abs(Y(k,3)-0)<1e-2; % Be careful of 0, that is z=0, namely, on the plane of x-y, the Poincare sections we chose in this paper, 
%which can be selected any other Poincare section if you like, e.g. x,y,z=0 or others!
Z=[Z Y(k,1)+i*Y(k,2)]; 
end
end
plot(Z,'.','markersize',2)
title('Chu system's Poincare map on the plane of z=0')
xlabel('x'),ylabel('y')'自