Initialization of function on Real element

dolfinx
1

Hi All,

I’m attempting to set an initial value for a Lagrange multiplier, defined as a function on a Real element space (using most recent dolfinx built from source). Normally I’d initialize by interpolating, but this doesn’t seem to work for real elements:

from dolfinx import mesh, fem
from mpi4py import MPI
import ufl

domain = mesh.create_unit_cube(MPI.COMM_WORLD, nx = 5, ny = 5, nz = 5,
                             cell_type=mesh.CellType.tetrahedron)
fe_p = ufl.FiniteElement("R", domain.ufl_cell(), 0)
V = fem.FunctionSpace(domain, fe_p)

def init_val(x):
    values = np.zeros(x.shape)
    return values

l_multiplier = fem.Function(V)
l_multiplier.interpolate(init_val)

RuntimeError: Cannot get interpolation points - no Basix element available. Maybe this is a mixed element?

Is there any way around this? Thanks!

2

Sorry for the late answer, it seems like Real elements are simply unsupported in dolfinx (see this post), but there’s a lone ranger out there with a merge request (see here).