choice functions for different n

F1:
F2: f(r)=exp(log(2)*(r*0.0065-4.0))
F3: f(r)=exp(log(2)*(r*0.016-3.0))
F4: f(r)=exp(log(2)*(r*0.0184-3.0))
F5: f(r)=exp(log(2)*(r*0.016-3.0))
F6: f(r)=exp(log(2)*(r*0.0125-3.0))
F7: f(r)=exp(log(2)*(r*0.0094-3.0))
F8: f(r)=exp(log(2)*(r*0.007-3.0))
F9: f(r)=exp(log(2)*(r*0.0053-3.0))
F10:f(r)=exp(log(2)*(r*0.0041-3.0))
F11:f(r)=exp(log(2)*(r*0.0033-3.0))
F12:f(r)=exp(log(2)*(r*0.0027-3.0))
