assemble_matrix compute_nuH_norm init_impl m_A m_default_pc_failure_count m_default_pc_failure_max_count m_KSP m_nuH_old m_nuh_viewer m_regional_mode m_velocity_old pc_setup_asm pc_setup_bjacobi picard_iteration picard_manager picard_strategy_regularization solve SSAFD update_nuH_viewers write_system_petsc ~SSAFD

compute_nuH_norm() std::array< double, 2 > pism::stressbalance::SSAFD::compute_nuH_norm ( const array::Staggered &  nuH, array::Staggered &  nuH_old  ) protected Compute the norm of nu H and the norm of the change in nu H. Verification and PST experiments suggest that an \(L^1\) criterion for convergence is best. For verification there seems to be little difference, presumably because the solutions are smooth and the norms are roughly equivalent on a subspace of smooth functions. For PST, the \(L^1\) criterion gives faster runs with essentially the same results. Presumably that is because rapid (temporal and spatial) variation in \(\nu H\) occurs at margins, occupying very few horizontal grid cells. For the significant (e.g.~in terms of flux) parts of the flow, it is o.k. to ignore a bit of bad behavior at these few places, and \(L^1\) ignores it more than \(L^2\) (much less \(L^\infty\), which might not work at all). Note: clobbers nuH_old – it is used to compute the change in nu H. Definition at line 577 of file SSAFD.cc. References pism::array::Array::add(), pism::Component::m_grid, and pism::array::Array::norm(). Referenced by picard_manager().