In antiferroelectric liquid crystal displays either V-shaped switching or tri-state switching characteristics are possible. Both types of states may be locally stable at constant voltage. However if they exist in different region of a pixel separated by a wall, the lowest energy state will grow by wall motion. It is thus important to be able to calculate accurately the energy of stationary states. We present three ways of calculating the Gibb`s free energy: by total simulation of non-stationary states, by partial simulation and calculation of the stationary states based on energy relations, and by analytical expressions of stationary V-shape states. This allows to check the accuracy of the simulations.