Transition from MeshFunction in Fenicsx

dolfinx
1

With Fenics I used the functionnality below to initialize material properties before assigning them for multi-materials:

my_mask = mesh.MeshFunction('size_t', mesh, 3, mesh.domains())
my_mask.set_all(2)

but MeshFunction seems to have disappeared from Fenicsx lately and after going through the documentation at https://jsdokken.com/dolfinx-tutorial/chapter3/subdomains.html I still can’t figure out how to do the same in Fenicsx.
Any hint in the right direction would be greatly appreciated!

2

The MeshFunction has been replaced by MeshTags, for various reasons, discussed here:MeshValueCollection in dolfinx - #2 by dokken

What you would like to do is easily achieved with the following (v0.6.0 syntax)

import dolfinx
from mpi4py import MPI
import numpy as np

mesh = dolfinx.mesh.create_unit_square(MPI.COMM_WORLD, 10, 10)

cell_map = mesh.topology.index_map(mesh.topology.dim)
num_cells_on_process = cell_map.size_local + cell_map.num_ghosts
cells = np.arange(num_cells_on_process, dtype=np.int32)
my_mask = dolfinx.mesh.meshtags(mesh, mesh.topology.dim, cells, np.full_like(cells, 2))
print(my_mask.values)
2 Likes
3

Yes, it’s exactly that, thank you!