I am having trouble expressing a distribution inside the model block. Hence I am not able to upload the mod file. But this is what I want do.

I have an equation

Q(t) = pi(t) *p_h + (1-pi(t))*p_l

Where pi(t) is probability with which model takes the value p_h.

Pi(t) ~F(y(t) - y_bar)

Where F is a CDF with argument y(t) - y_bar where y is output and y_bar is steady state output. How do i express F in the model block? Can someone help please.

Thank you.