Imposing a discontinuity at interface using DG method

[dokken]

I would suggest searching on the forum for your error message, as it is already covered at:

Linear Elasticity Tutorial w/ Quadratic Tetrahedrals

Use dolfinx.io.VTXWriter instead of xdmffile if you are not using isoparametric elements.

and

Cannot write function to XDMF with DG elements

This is an explicit change to highlight the limitations of the XDMF file format, as in comparison to VTX. In DOLFINx<0.7.0 any function was interpolated into the function space of the mesh geometry (N-th order Lagrange space, N usually 1). Now you have to interpolate this function into (“CG”, 1) explicitly to save it to xdmf, or use the VTXWriter, which supports arbitrary order “CG”/“DG” elements.

[Quentin]

thanks I will have a look.

this being said I find the vtu less convenient when it comes to parrallel processing.

It is a pity that xdmf is not maintained anymore

[dokken]

@Quentin

this being said I find the vtu less convenient when it comes to parrallel processing.

Have you tested VTXWriter?

[Quentin]

No but I definitely will.

According to this post

Cannot write function to XDMF with DG elements

It would seem it has to do with needing the MPI version Is this the MPI version?

it seems that there might be paraview issue but should be manageable

[RemDelaporteMathurin]

Hi Quentin, I think the Paraview team fixed this and VTX should be readable (or will) without the MPI version

[Quentin]

Hi guys,

I tried this format using

writer = VTXWriter(mesh.comm, "Temperature.bp", [u], "BP4")
writer.write(0.0)

It writes me several files, and paraview can read a .idx file, but when I try to open it, I get the following error

Any idea about how to solve that ?

Thanks,

Quentin

[dokken]

See Issues visualizing multiple fields stored in single XDMF file [dolfinx] - #5 by dokken

[Quentin]

indeed a more recent version of Paraview solves the problem