def test_initialize_fneq(Case, dtype_device):
dtype, device = dtype_device
lattice = Lattice(D2Q9, device, dtype)
if "3D" in Case.__name__:
lattice = Lattice(D3Q27, dtype=dtype, device=device)
flow = Case(resolution=40,
reynolds_number=1000,
mach_number=0.1,
lattice=lattice)
collision = BGKCollision(lattice, tau=flow.units.relaxation_parameter_lu)
streaming = StandardStreaming(lattice)
simulation_neq = Simulation(flow=flow,
lattice=lattice,
collision=collision,
streaming=streaming)
pre_rho = lattice.rho(simulation_neq.f)
pre_u = lattice.u(simulation_neq.f)
pre_ke = lattice.incompressible_energy(simulation_neq.f)
simulation_neq.initialize_f_neq()
post_rho = lattice.rho(simulation_neq.f)
post_u = lattice.u(simulation_neq.f)
post_ke = lattice.incompressible_energy(simulation_neq.f)
tol = 1e-6
assert torch.allclose(pre_rho, post_rho, rtol=0.0, atol=tol)
assert torch.allclose(pre_u, post_u, rtol=0.0, atol=tol)
assert torch.allclose(pre_ke, post_ke, rtol=0.0, atol=tol)
if Case is TaylorGreenVortex2D:
error_reporter_neq = ErrorReporter(lattice, flow, interval=1, out=None)
error_reporter_eq = ErrorReporter(lattice, flow, interval=1, out=None)
simulation_eq = Simulation(flow=flow,
lattice=lattice,
collision=collision,
streaming=streaming)
simulation_neq.reporters.append(error_reporter_neq)
simulation_eq.reporters.append(error_reporter_eq)
simulation_neq.step(10)
simulation_eq.step(10)
error_u, error_p = np.mean(np.abs(error_reporter_neq.out),
axis=0).tolist()
error_u_eq, error_p_eq = np.mean(np.abs(error_reporter_eq.out),
axis=0).tolist()
assert (error_u < error_u_eq)
def test_divergence(stencil, dtype_device):
dtype, device = dtype_device
lattice = Lattice(stencil, dtype=dtype, device=device)
flow = DecayingTurbulence(50, 1, 0.05, lattice=lattice, ic_energy=0.5)
collision = BGKCollision(lattice, tau=flow.units.relaxation_parameter_lu)
streaming = StandardStreaming(lattice)
simulation = Simulation(flow=flow,
lattice=lattice,
collision=collision,
streaming=streaming)
ekin = flow.units.convert_incompressible_energy_to_pu(
torch.sum(lattice.incompressible_energy(
simulation.f))) * flow.units.convert_length_to_pu(1.0)**lattice.D
u0 = flow.units.convert_velocity_to_pu(lattice.u(simulation.f)[0])
u1 = flow.units.convert_velocity_to_pu(lattice.u(simulation.f)[1])
dx = flow.units.convert_length_to_pu(1.0)
grad_u0 = torch_gradient(u0, dx=dx, order=6).cpu().numpy()
grad_u1 = torch_gradient(u1, dx=dx, order=6).cpu().numpy()
divergence = np.sum(grad_u0[0] + grad_u1[1])
if lattice.D == 3:
u2 = flow.units.convert_velocity_to_pu(lattice.u(simulation.f)[2])
grad_u2 = torch_gradient(u2, dx=dx, order=6).cpu().numpy()
divergence += np.sum(grad_u2[2])
assert (flow.ic_energy == pytest.approx(lattice.convert_to_numpy(ekin),
rel=1))
assert (0 == pytest.approx(divergence, abs=2e-3))