ex02ch4.m

these codes are for solving OED with matlab

function sol = ex02ch4(alpha,b,c)
e = 1 - c/b;   % Equilibrium point.
sol = dde23(@ddes,7,alpha,[0, 60],[],b,c);
plot(sol.x,sol.y,[0, 60],[e, e],'r')
legend('y(t)','1 - c/b')
title(['Cooke Epidemic Model with \alpha = ',num2str(alpha) ...
       ' , b = ',num2str(b),' , c = ',num2str(c)])
xlabel('time t')
%===============================================
function v = ddes(t,y,Z,b,c)
v = b * Z * (1 - y) - c * y;