(color online) The variations of the average fidelities versus scaled standard deviations of inhomogeneous parameter p. (a) p = V_Rr, random-initial-based-method. (b) p = V_Rr, trace-operator-based method. (c) p = V_rr, random-initial-based-method. (d) p = V_rr, trace-operator-based method. The standard parameters are chosen as V_Rr/Ω = 18, Ω/V_rr = 20, and γ = 10⁻³Ω. For the random-initial-based method, 100 groups of normalized initial states are considered.