Hi everyone ! When using discontinuous finite element method（DG） for interior surface integral(dS),we must use (‘-’) and (‘+’) to restrict. So I want to know the principle of dolfinx partitioning (‘-’)and(‘+’)? Further,When running programs in parallel,will (‘-’) and (‘+’) change after grid pa…

Thanks dokken! Running an interior surface integral in parallel yields different results than running it in series. Is this because after partitioning the grid, (‘-’) and (‘+’) have changed?

Are you using dolfinx.mesh.GhostMode.shared_facet when reading in/creating your mesh? Usually in DG methods, there are a combination of avg and jump terms which means that the orientation doesn’t matter. The consistent “+” and “-” orientation is usually only important if you try to do a one-sided …

I use dolfinx.mesh GhostMode.shared_facet read_mesh = io.XDMFFile(MPI.COMM_WORLD,"kk.xdmf" ,"r") msh=read_mesh.read_mesh(name="Grid") It be used as the default parameter. I need to use one-sided interior integral (dS) instead of ds. The serial program, I have tested and it is correct. If it is…

I would need a minimal reproducible example to see what goes wrong in your case, as it there shouldn’t be any parallel problems with this approach.

My grid is a spherical mesh, and the three spherical surfaces with radii ri(=0.538),ro(=1.538) and 5*ro divide the mesh into three subdomains. This example only focuses on the second subdomain (ri<r<ro). Firstly, I create custom interior and boundary surfaces tag： [image] ds should be used on t…

How does dolfinx distinguish between ('-') and ('+')?

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dokken October 21, 2024, 5:35am 2

See: Consistent side of interior boundaries with dolfinx - #2 by dokken

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How does dolfinx distinguish between ('-') and ('+')?

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