% This m-file computes a streak line and path line for the oscillating vortex,
%starting from the point y0=(1,1), for epsilon=.7 and omega=5. The time varies
%from 0 to 10 units.
global eps om;
eps=.7;
om=5;
y0=[1;1];
for i=1:200;
   tspan=[(i-1)/20 10];
   [t,y]=ode45('lagvort',tspan,y0);
   n=length(t);
   xp(i)=y(n,1);
   yp(i)=y(n,2);
end
subplot(1,2,1);
plot(xp,yp),title('streak line');
tspan=[0 10];
[t,z]=ode45('lagvort',tspan,y0);
subplot(1,2,2);
plot(z(:,1),z(:,2)),title('path line')
