When the default prolongation type is chosen in a dynamical spacetime evolution, hydrodynamic and GRMHD fields can suffer from spurious oscillations generated at AMR refinement boundaries due to the high-order Lagrange polynomial prolongation.
This patch adds a simple Lagrange third-order prolongation operator to Carpet, which is more suitable for hydro and GRMHD field prolongations.
I would like for this to be the default prolongation type for the evolved conservative variables in IllinoisGRMHD and GiRaFFE, starting in the next ETK release (2018 H2), as it reduces numerical noise at AMR boundaries.
When the default prolongation type is chosen in a dynamical spacetime evolution, hydrodynamic and GRMHD fields can suffer from spurious oscillations generated at AMR refinement boundaries due to the high-order Lagrange polynomial prolongation.
This patch adds a simple Lagrange third-order prolongation operator to Carpet, which is more suitable for hydro and GRMHD field prolongations.
I would like for this to be the default prolongation type for the evolved conservative variables in IllinoisGRMHD and GiRaFFE, starting in the next ETK release (2018 H2), as it reduces numerical noise at AMR boundaries.