Magnetic modeling can be carried out at the physical level or the phenomenological level. At both levels, the models are coupled to Maxwell's equations, which characterize the working relationships in the fields. In physical modeling, the parameters are dependent upon the choice of materials and the physical principles involved. In phenomenological modeling, the material behavior is identified parametrically using mathematical formulas which characterize the material's behavior. The latter method gives general physical insights into the magnetization process and is computationally much more efficient, but not every parameter has a physical meaning.