drag drag_with_derivative IceBasalResistancePlasticLaw m_plastic_regularize print_info ~IceBasalResistancePlasticLaw

drag_with_derivative() void pism::IceBasalResistancePlasticLaw::drag_with_derivative ( double  tauc, double  vx, double  vy, double *  beta, double *  dbeta  ) const virtual Compute the drag coefficient and its derivative with respect to $\alpha = \frac 1 2 (u_x^2 + u_y^2)$. $$\begin{align*} \beta &= \frac{\tau_{c}}{|\mathbf{u}|} = \tau_{c}\cdot (|\mathbf{u}|^{2})^{-1/2}\\ \diff{\beta}{\frac12 |\mathbf{u}|^{2}} &= -\frac{1}{|\mathbf{u}|^{2}}\cdot \beta \end{align*}$$ Reimplemented in pism::IceBasalResistancePseudoPlasticLaw, and pism::IceBasalResistanceRegularizedLaw. Definition at line 60 of file basal_resistance.cc. References m_plastic_regularize, and pism::square(). Referenced by pism::stressbalance::Blatter::jacobian_basal(), and pism::stressbalance::SSAFEM::PointwiseNuHAndBeta().