* Example for n with the units identical 

bind 
MTTF 1/(10*10^4)
MTTR 1/(1.25*10^8)
end

block ser(n) 
comp Unit ss_unavail(1/MTTF, 1/MTTR)
kofn sys n,n,Unit
end

func U(n) sysprob(ser;n)
func A(n) 1-U(n)

* variable named downtime is the system downtime in minutes per year
func downtime(n) 60*8760*U(n)

* Mean Time To System Failure
func MTTSF(n)  MTTF/n

* Mean Time To System Restoration
func MTTSR(n)   U(n)* MTTSF(n) / A(n) 

* vary the value n 
loop n,2,10
  expr  A(n), U(n) ,downtime(n), MTTSF(n), MTTSR(n)
end

end

