% Plot outcomes of Van der Pol oscillator for µ varying bewteen 0 and 2.
% 
% The van der Pol equation (y_1)"-µ*(1-(x_1)^2)*y'+(y_1)=0 is equivalent 
%    to a system of coupled first-order differential equations
%       (y_1)'=(y_2)
%       (y_2)'=µ*[1-(y_1)^2]*(y_2)-(y_1).
%
%    for 0<µ<2.
%
% see also "vdpeqMU.m"


disp(' ')
disp(' ')
disp('To Stop Simulation, Press "Ctrl+c" in the Command Window ... ')
disp(' ')
disp(' ')

x0=[0.1 0.1];

global mu

for mu=0:0.01:2;

    pause(0.01)
    
    [t,Q] = ode45(@vdpeqMU,[0 60],x0);
    
subplot(121);
plot(t,Q(:,1),'-',t,Q(:,2),'r-.');
xlabel('time t');
ylabel('solution y_1 and y_2');
title(['Van der Pol with 0 \leq \mu \leq 2: \mu= ', num2str(mu)]);

subplot(122);
plot(Q(:,1),Q(:,2));
xlabel('y_1');
ylabel('y_2');

end


% "Complex and Chaotic Nonlinear Dynamics. 
% Advances in Economics and Finance, 
% Mathematics and Statistics" 
% T.Vialar, Springer 2009
% Copyright(c).