1. A computer-implemented method for modeling a circuit including a resistive random access memory (RRAM) cell, the method comprising: providing a circuit including at least one RRAM cell in a display area of a computer system, the RRAM cell being associated with a first internal state variable; calling a sub-circuit module that represents the RRAM cell and has a first component that corresponds to a formula for solving the first internal state variable; modeling a characteristic of the circuit using the sub-circuit module; adjusting the circuit using a result of the modeling step; and storing the adjusted circuit in a storage location associated with the computer system.