def test_assemble_derivatives():
"""This test checks the original_coefficient_positions, which may change
under differentiation (some coefficients and constants are
eliminated)"""
mesh = dolfinx.generation.UnitSquareMesh(dolfinx.MPI.comm_world, 12, 12)
Q = dolfinx.FunctionSpace(mesh, ("Lagrange", 1))
u = dolfinx.Function(Q)
v = ufl.TestFunction(Q)
du = ufl.TrialFunction(Q)
b = dolfinx.Function(Q)
c1 = function.Constant(mesh, [[1.0, 0.0], [3.0, 4.0]])
c2 = function.Constant(mesh, 2.0)
with b.vector.localForm() as b_local:
b_local.set(2.0)
# derivative eliminates 'u' and 'c1'
L = ufl.inner(c1, c1) * v * dx + c2 * b * inner(u, v) * dx
a = derivative(L, u, du)
A1 = dolfinx.fem.assemble_matrix(a)
A1.assemble()
a = c2 * b * inner(du, v) * dx
A2 = dolfinx.fem.assemble_matrix(a)
A2.assemble()
assert (A1 - A2).norm() == pytest.approx(0.0, rel=1e-12, abs=1e-12)
def test_basic_assembly_constant():
"""Tests assembly with Constant
The following test should be sensitive to order of flattening the
matrix-valued constant.
"""
mesh = dolfinx.generation.UnitSquareMesh(dolfinx.MPI.comm_world, 5, 5)
V = function.FunctionSpace(mesh, ("Lagrange", 1))
u, v = ufl.TrialFunction(V), ufl.TestFunction(V)
c = function.Constant(mesh, [[1.0, 2.0], [5.0, 3.0]])
a = inner(c[1, 0] * u, v) * dx + inner(c[1, 0] * u, v) * ds
L = inner(c[1, 0], v) * dx + inner(c[1, 0], v) * ds
# Initial assembly
A1 = dolfinx.fem.assemble_matrix(a)
A1.assemble()
b1 = dolfinx.fem.assemble_vector(L)
b1.ghostUpdate(addv=PETSc.InsertMode.ADD, mode=PETSc.ScatterMode.REVERSE)
c.value = [[1.0, 2.0], [3.0, 4.0]]
A2 = dolfinx.fem.assemble_matrix(a)
A2.assemble()
b2 = dolfinx.fem.assemble_vector(L)
b2.ghostUpdate(addv=PETSc.InsertMode.ADD, mode=PETSc.ScatterMode.REVERSE)
assert (A1 * 3.0 - A2 * 5.0).norm() == pytest.approx(0.0)
assert (b1 * 3.0 - b2 * 5.0).norm() == pytest.approx(0.0)