I can't run this on my machine without the function ddex1histd, but here's my best idea:
Have the function return sol and assign it to some value in your workspace.
function sol = ddex1
global k1 k2 k3 zf wf a b g d f m w wn
a=-0.01; b=0.05; g=14.4108; d=3.2746; f=0.01;m=0.89663; w=3.06309;
wn=3.06309;wf=3.1;zf=0.1; k1=-0.1; k2=1;k3=-0.5;
sol = dde23(@ddex1tde,[0.1],@ddex1histd,[0, 1000])
% figure;
plot(sol.x,sol.y(1,:))
xlabel('time t');
ylabel('solution y');
Function call:
out = ddex1()
