.FluxTubesExtension.Types.Approximation .FluxTubesExtension.Types.ApproximationEnumeration defining the approximation of soft magnetic chracateristics
type Approximation = enumeration(Roschke "mu_r(B) acc. to Roschke", Macfadyen "B(H) acc. to Macfadyen", PiecewiseLinear "Piecewise linear interpolation");