Function test_custom_vector_element

python/test/unit/fem/test_interpolation.py:810–849

Test interpolation into an element with a value size that uses an identity map.

()

def test_custom_vector_element():
    """Test interpolation into an element with a value size that uses an identity map."""
    mesh = create_unit_square(MPI.COMM_WORLD, 10, 10)
    wcoeffs = np.eye(6)
    x = [[], [], [], []]
    x[0].append(np.array([[0.0, 0.0]]))
    x[0].append(np.array([[1.0, 0.0]]))
    x[0].append(np.array([[0.0, 1.0]]))
    for _ in range(3):
        x[1].append(np.zeros((0, 2)))
    x[2].append(np.zeros((0, 2)))
    M = [[], [], [], []]
    for _ in range(3):
        M[0].append(np.array([[[[1.0]], [[0.0]]], [[[0.0]], [[1.0]]]]))
    for _ in range(3):
        M[1].append(np.zeros((0, 2, 0, 1)))
    M[2].append(np.zeros((0, 2, 0, 1)))
    e = custom_element(
        basix.CellType.triangle,
        [2],
        wcoeffs,
        x,
        M,
        0,
        basix.MapType.identity,
        basix.SobolevSpace.H1,
        False,
        1,
        1,
        dtype=default_real_type,
    )

    V = functionspace(mesh, e)
    gdim = mesh.geometry.dim
    W = functionspace(mesh, ("Lagrange", 1, (gdim,)))
    v = Function(V)
    w = Function(W)
    v.interpolate(lambda x: (x[0], x[1]))
    w.interpolate(lambda x: (x[0], x[1]))
    assert np.abs(assemble_scalar(form(ufl.inner(v - w, v - w) * ufl.dx))) == pytest.approx(0)


@pytest.mark.skip_in_parallel