Assign values to subdomain id

[dokken]

See:

How to define different materials / importet 3D geometry (gmsh)

Following Dolfinx discontinous expression, this code can be modified for the syntax in dolfin as follows: import dolfin mesh = dolfin.UnitCubeMesh(9, 9, 9) V = dolfin.FunctionSpace(mesh, "DG", 0) v = dolfin.Function(V) x = V.tabulate_dof_coordinates() mf = dolfin.MeshFunction("size_t", mesh, mesh.topology().dim()) class Obstacle(dolfin.SubDomain): def inside(self, x, on_boundary): return (dolfin.between(x[1], (0.2, 0.7)) and dolfin.between(x[0], (0.3, 0.7))) Obstacl…

or

Dolfinx discontinous expression

You could for instance do the following for geometrical search: import dolfinx import dolfinx.io mesh = dolfinx.UnitSquareMesh(dolfinx.MPI.comm_world, 9, 9) V = dolfinx.FunctionSpace(mesh, ("DG", 0)) v = dolfinx.Function(V) x = V.tabulate_dof_coordinates() for i in range(x.shape[0]): midpoint = x[i,:] if midpoint[0]> 0.5 and midpoint[1]>0.25: v.vector.setValueLocal(i, 2) else: v.vector.setValueLocal(i, 1) dolfinx.io.XDMFFile(dolfinx.MPI.comm_world, "DG.xdmf").write…