微分方程-司守寇

非刚性 ode45

function dy=vdp1(t,y);
dy=[y(2);(1-y(1)^2)*y(2)-y(1)];

[T,Y]=ode45('vdp1',[0 20],[2;0]);
plot(T,Y(:,1),'-',T,Y(:,2),'--')
title('Solution of van der Pol Equation,mu=1');
xlabel('time t');
ylabel('solution y');
legend('y1','y2');

刚性 ode15

function dy=vdp1000(t,y);
dy=[y(2);1000*(1-y(1)^2)*y(2)-y(1)];

[t,y]=ode15s('vdp1000',[0 3000],[2;0]);
plot(t,y(:,1),'o')
title('Solution of van der Pol Equation,mu=1000');
xlabel('time t');
ylabel('solution y(:,1)');