#2030: Multi-block boundaries leave uninitialized boundary points ------------------------------------+--------------------------------------- Reporter: eschnett | Owner: Type: defect | Status: new Priority: major | Milestone: Component: EinsteinToolkit thorn | Version: development version Resolution: | Keywords: ------------------------------------+---------------------------------------
Comment (by eschnett):
Yes, this is the same problem.
You can avoid it by using both {{{initial_boundary_condition="scalar"}}} and {{{rhs_boundary_condition="scalar"}}}, and by not using any symmetries. Any other multi-block case, i.e. either using bitant mode, or using extrapolation for the initial boundary condition or radiative for the rhs boundary condition, should trigger the issue.
The second bug compounds the issue, because the initial boundary condition is not handled correctly even in the scalar case. I will propose a patch soon.
As you say, the best current solution for this problem is to apply the boundary conditions twice, both before and after multi-block interpolation. The true solution, which is not supported by Cactus's boundary conditions, is to distinguish between faces, edges, and corners, and to apply some of these before and the others after multi-block interpolation. While this still requires boundary conditions twice in the schedule, they will be executed only once per boundary point.