void eval(PorosityData const &poro_data, SolidDensityData const &rho_S_data, LiquidDensityData const &rho_L_data, SaturationData const &S_L_data, SaturationDataDeriv const &dS_L_data, GravityData< DisplacementDim > &out) const
Eigen::Vector< double, DisplacementDim > specific_body_force