Dolfin can't successfully read the xdmf file consisted with tetra and wedge mesh

mesh
1

Continuing the discussion from Gmshio can't successfully read the msh file created by Gmsh:

When I exported the mesh as .xdmf using meshio, and used dolfin to read the file, it dosen’t work either when the xdmf could be opened with paraview. I tried to export only tetrahedra or wedge, and only the file contained tetraIs could be read. fenics couldn’t read the msh file that contains two and more kinds of mesh?

import meshio
import matplotlib.pyplot as pt
msh = meshio.read("msh_generate.msh")
#mesh
meshio.write("mesh.xdmf", meshio.Mesh(points=msh.points, cells={"tetra": msh.cells["tetra"],"wedge": msh.cells["wedge"]}))
#boundary face
meshio.write("mf.xdmf", meshio.Mesh(points=msh.points, cells={"triangle": msh.cells["triangle"],"quad": msh.cells["quad"]},cell_data={"triangle": {"name_to_read": msh.cell_data["triangle"]["gmsh:physical"]},"quad": {"name_to_read": msh.cell_data["quad"]["gmsh:physical"]}}))
#boundary cell
meshio.write("cf.xdmf", meshio.Mesh(points=msh.points, cells={"tetra": msh.cells["tetra"],"wedge": msh.cells["wedge"]},cell_data={"tetra": {"name_to_read":msh.cell_data["tetra"]["gmsh:physical"]},"wedge": {"name_to_read":msh.cell_data["wedge"]["gmsh:physical"]}}))


from dolfin import * 
mesh = Mesh()
with XDMFFile("mesh.xdmf") as infile:
    infile.read(mesh)
mvc = MeshValueCollection("size_t", mesh, 2) 
with XDMFFile("mf.xdmf") as infile:
    infile.read(mvc, "name_to_read")
mf = cpp.mesh.MeshFunctionSizet(mesh, mvc)
boundary_markers=MeshFunction("size_t",mesh,mvc)
#print(boundaries.value())
mvc = MeshValueCollection("size_t", mesh, 3)
with XDMFFile("cf.xdmf") as infile:
    infile.read(mvc, "name_to_read")
cf = cpp.mesh.MeshFunctionSizet(mesh, mvc)

The error is as follows:

Traceback (most recent call last):
  File "meshfile.py", line 15, in <module>
    infile.read(mesh)
RuntimeError: 

*** -------------------------------------------------------------------------
*** DOLFIN encountered an error. If you are not able to resolve this issue
*** using the information listed below, you can ask for help at
***
***     fenics-support@googlegroups.com
***
*** Remember to include the error message listed below and, if possible,
*** include a *minimal* running example to reproduce the error.
***
*** -------------------------------------------------------------------------
*** Error:   Unable to recognise cell type.
*** Reason:  Unknown value "mixed".
*** Where:   This error was encountered inside XDMFFile.cpp.
*** Process: 0
*** 
*** DOLFIN version: 2019.1.0
*** Git changeset:  2e001bd1aae8e14d758264f77382245e6eed04b0
*** --------------------------------------------------------------
2

Dolfin does not support wedge meshes or Mixed meshes.

3

Can other methods be used to implement the boundary layer grid over there? Neither dolfin nor dolfinx can calculate the simulation model with boundary layers?

4

You would have make a mesh consisting of either only tetrahedra or hexahedral elements.

There has been done some work on supporting meshes with mixed cell types, but the work is not complete

5

Can’t both dolfin and dolfinx recognize wedge or mixed cell types? If that’s the case, I’m really looking forward to the new version.

6

As @dokken said, neither of them currently supports that. There is no ETA on when this feature will land in the new version.