Quadrature function space

dolfinx
6

Hello!

I’ve wanted to come back to Quadrature function spaces as I’ve seen that they are now enabled in latest dolfinx.

Nevertheless, I’ve used above MWE and tried to do a simple operation of interpolating a constant to the space, and get the error RuntimeError: Cannot get interpolation points - no Basix element available. Maybe this is a mixed element? if the last line of the following MWE is executed (dolfinx Docker image from today):

#!/usr/bin/env python3
from dolfinx import BoxMesh, FunctionSpace, Function
import dolfinx.cpp.mesh
from mpi4py import MPI
import numpy as np
from ufl import FiniteElement

comm = MPI.COMM_WORLD

mesh = BoxMesh(comm, [np.array([0.0, 0.0, 0.0]),np.array([2.0, 1.0, 1.0])], [5, 5, 5],
               dolfinx.cpp.mesh.CellType.tetrahedron, dolfinx.cpp.mesh.GhostMode.none)

P_q = FiniteElement("Quadrature", mesh.ufl_cell(), degree=1, quad_scheme="default")
V_q = FunctionSpace(mesh, P_q)

def expr(x): return 1.

x = Function(V_q)
x.interpolate(expr)

Is there any specific new syntax on how interpolation to Quadrature function spaces has to happen?

Thanks!

Best,
Marc