This PR enables higher-order VTK output for use with ParaView.
Specifically, the function DGBase::output_results_vtk() has been modified to select the number of subdivisions from the maximum of grid_degree and poly_degree, which allows higher-order results to be written even if the grid is straight.
A parameter, enable_higher_order_vtk_output, is added to toggle whether higher-order results are written, which is false by default. In some cases, it may be sufficient to visualize only (bi/tri)linear interpolations, such as if the grid is fine. As well, not all vtk visualization programs support higher-order Lagrange elements. ParaView is able to (see this deal.ii wiki page ). From my testing, VisIt cannot handle higher-order solutions, and is unable to interpret the vtk files. I'm unsure about other vtk programs.
Additionally, I have added an optional parameter to DGBase::output_results_vtk(), current_time. This can be used to add the simulation time to the visualization. If current_time isn't passed, the time is written as 0.0, consistent with previous behaviour. On ParaView, select Filters->Annotate Global Data to show the current time.
To demonstrate the new behaviour, I've attached a visualization of MPI_VISCOUS_TAYLOR_GREEN_VORTEX_ENERGY_CHECK_LONG after 400 iterations, both with and without higher-order output.
This PR enables higher-order VTK output for use with ParaView.
Specifically, the function
DGBase::output_results_vtk()has been modified to select the number of subdivisions from the maximum ofgrid_degreeandpoly_degree, which allows higher-order results to be written even if the grid is straight.A parameter,
enable_higher_order_vtk_output, is added to toggle whether higher-order results are written, which is false by default. In some cases, it may be sufficient to visualize only (bi/tri)linear interpolations, such as if the grid is fine. As well, not all vtk visualization programs support higher-order Lagrange elements. ParaView is able to (see this deal.ii wiki page ). From my testing, VisIt cannot handle higher-order solutions, and is unable to interpret the vtk files. I'm unsure about other vtk programs.Additionally, I have added an optional parameter to
DGBase::output_results_vtk(),current_time. This can be used to add the simulation time to the visualization. Ifcurrent_timeisn't passed, the time is written as0.0, consistent with previous behaviour. On ParaView, select Filters->Annotate Global Data to show the current time.To demonstrate the new behaviour, I've attached a visualization of
MPI_VISCOUS_TAYLOR_GREEN_VORTEX_ENERGY_CHECK_LONGafter 400 iterations, both with and without higher-order output.