Paraview crashes for xdmf file with anisotropic mesh

ParaView Support
3

I figured it out. The problem is, that if one chooses to create a mesh in fenicsX using a special argument of the xdmf-writer, then - under some choice of the element number/mesh structure - the xdmf file is corrupted.

If one creates a mesh like this:

msh = create_box(MPI.COMM_WORLD, 
                        [[0.0, 0.0, 0.0], [Lx, Ly, Lz]], 
                        [Nx,Ny,Nz],
                        cell_type=CellType.hexahedron)

Then, the “bad” way to write to xdmf is

from dolfinx import io
xdmf_file = io.XDMFFile(msh.comm, "my_file.xdmf", "w", encoding=io.XDMFFile.Encoding.ASCII)
xdmf_file.write_mesh(msh)
xdmf_file.close()

while the good way (the one that worked for me) is this:

from dolfinx import io
xdmf_file = io.XDMFFile(msh.comm, "my_file.xdmf", "w")
xdmf_file.write_mesh(msh)
xdmf_file.close()