I’m working on a filter which requires a rectilinear grid with ghost cells and I want to know which cell is a ghost cell when running an algorithm on the dataset. To my current understanding the vtkGhostType array is meant for exactly this purpose.
But this array is missing some times. I.e. it is set when I open a *.vtr file and then apply my filter which requires a ghost level, but it is not set when using the Xdmf2 reader instead.
Who is responsible for setting the vtkGhostType array and how can I ensure to have the vtkGhostType array available?
Seems the pipeline is generating it if the source sets CAN_PRODUCE_SUB_EXTENT():
In the wiki I found the explanation “[…] Such readers should not set CAN_PRODUCE_SUB_EXTENT() but set CAN_HANDLE_PIECE_REQUEST() and handle both UPDATE_EXTENT() and pieces/ghosts internally. […]” https://vtk.org/Wiki/VTK/Parallel_Pipeline#Structured_Data_Readers_and_Filters
The Xdmf2 Reader seems to be such a reader which just sets CAN_HANDLE_PIECE_REQUEST(), does this mean the Xdmf2 Reader has a bug by not setting vtkGhostType or is this something I must do in the custom filter?