OK, I used the "ic" parameter in the AC simulation. When it is done, then I go to Results > Annotate > DC Node Voltages. The voltage shown on the cap is not the voltage I initialized. It seems showing the voltage on the cap in DC condition. Is it right? Also when I go to Results > Annotate > DC Operating Points, it does not show any information (current, voltage) on the cap. The cap is from the "analogLib" library.
Can initial conditions be used in AC simulation? Does it use the initial condition I put in to calculate the AC performance?