def test_stream_only_kernel(streaming_pattern):
domain_size = (4, 4)
stencil = LBStencil(Stencil.D2Q9)
dh = ps.create_data_handling(domain_size, default_target=Target.CPU)
pdfs = dh.add_array('pdfs', values_per_cell=len(stencil))
pdfs_tmp = dh.add_array_like('pdfs_tmp', 'pdfs')
for t in get_timesteps(streaming_pattern):
accessor = get_accessor(streaming_pattern, t)
src = pdfs
dst = pdfs if is_inplace(streaming_pattern) else pdfs_tmp
dh.fill(src.name, 0.0)
dh.fill(dst.name, 0.0)
stream_kernel = create_stream_only_kernel(stencil, src, dst, accessor=accessor)
stream_func = create_kernel(stream_kernel).compile()
# Check functionality
acc_in = AccessPdfValues(stencil, streaming_dir='in', accessor=accessor)
for i in range(len(stencil)):
acc_in.write_pdf(dh.cpu_arrays[src.name], (1,1), i, i)
dh.run_kernel(stream_func)
acc_out = AccessPdfValues(stencil, streaming_dir='out', accessor=accessor)
for i in range(len(stencil)):
assert acc_out.read_pdf(dh.cpu_arrays[dst.name], (1,1), i) == i
def __init__(self, pdf_field, stencil, prev_timestep=Timestep.BOTH, streaming_pattern='pull',
index_dtype=np.int64, offsets_dtype=np.int64):
if prev_timestep == Timestep.BOTH and is_inplace(streaming_pattern):
raise ValueError('Cannot create index arrays for both kinds of timesteps for inplace streaming pattern '
+ streaming_pattern)
prev_accessor = get_accessor(streaming_pattern, prev_timestep)
next_accessor = get_accessor(streaming_pattern, prev_timestep.next())
outward_accesses = prev_accessor.write(pdf_field, stencil)
inward_accesses = next_accessor.read(pdf_field, stencil)
self._accesses = {'out': outward_accesses, 'in': inward_accesses}
self._pdf_field = pdf_field
self._stencil = stencil
self._dim = stencil.D
self._q = stencil.Q
self._coordinate_names = ['x', 'y', 'z'][:self._dim]
self._index_dtype = create_type(index_dtype)
self._offsets_dtype = create_type(offsets_dtype)
self._required_index_arrays = set()
self._required_offset_arrays = set()
self._trivial_index_translations, self._trivial_offset_translations = self._collect_trivial_translations()
def __init__(self,
lb_method,
data_handling,
pdf_field_name,
streaming_pattern='pull',
name="boundary_handling",
flag_interface=None,
target=Target.CPU,
openmp=True):
self._lb_method = lb_method
self._streaming_pattern = streaming_pattern
self._inplace = is_inplace(streaming_pattern)
self._prev_timestep = None
super(LatticeBoltzmannBoundaryHandling,
self).__init__(data_handling, pdf_field_name, lb_method.stencil,
name, flag_interface, target, openmp)
def test_fully_periodic_flow(target, stencil, streaming_pattern):
gpu = False
if target == Target.GPU:
gpu = True
# Stencil
stencil = LBStencil(stencil)
# Streaming
inplace = is_inplace(streaming_pattern)
timesteps = get_timesteps(streaming_pattern)
zeroth_timestep = timesteps[0]
# Data Handling and PDF fields
domain_size = (30, ) * stencil.D
periodicity = (True, ) * stencil.D
dh = create_data_handling(domain_size=domain_size,
periodicity=periodicity,
default_target=target)
pdfs = dh.add_array('pdfs', stencil.Q)
if not inplace:
pdfs_tmp = dh.add_array_like('pdfs_tmp', pdfs.name)
# LBM Streaming and Collision
lbm_config = LBMConfig(stencil=stencil,
method=Method.SRT,
relaxation_rate=1.0,
streaming_pattern=streaming_pattern)
lbm_opt = LBMOptimisation(symbolic_field=pdfs)
config = CreateKernelConfig(target=target)
if not inplace:
lbm_opt = replace(lbm_opt, symbolic_temporary_field=pdfs_tmp)
lb_collision = create_lb_collision_rule(lbm_config=lbm_config,
lbm_optimisation=lbm_opt,
config=config)
lb_method = lb_collision.method
lb_kernels = []
for t in timesteps:
lbm_config = replace(lbm_config, timestep=t)
lb_kernels.append(
create_lb_function(collision_rule=lb_collision,
lbm_config=lbm_config,
lbm_optimisation=lbm_opt))
# Macroscopic Values
density = 1.0
density_field = dh.add_array('rho', 1)
u_x = 0.01
velocity = (u_x, ) * stencil.D
velocity_field = dh.add_array('u', stencil.D)
u_ref = np.full(domain_size + (stencil.D, ), u_x)
setter = macroscopic_values_setter(lb_method,
density,
velocity,
pdfs,
streaming_pattern=streaming_pattern,
previous_timestep=zeroth_timestep)
setter_kernel = create_kernel(
setter, config=CreateKernelConfig(target=target,
ghost_layers=1)).compile()
getter_kernels = []
for t in timesteps:
getter = macroscopic_values_getter(lb_method,
density_field,
velocity_field,
pdfs,
streaming_pattern=streaming_pattern,
previous_timestep=t)
getter_kernels.append(
create_kernel(getter,
config=CreateKernelConfig(target=target,
ghost_layers=1)).compile())
# Periodicity
periodicity_handler = LBMPeriodicityHandling(
stencil, dh, pdfs.name, streaming_pattern=streaming_pattern)
# Initialization and Timestep
current_timestep = zeroth_timestep
def init():
global current_timestep
current_timestep = zeroth_timestep
dh.run_kernel(setter_kernel)
def one_step():
global current_timestep
# Periodicty
periodicity_handler(current_timestep)
# Here, the next time step begins
current_timestep = current_timestep.next()
# LBM Step
dh.run_kernel(lb_kernels[current_timestep.idx])
# Field Swaps
if not inplace:
dh.swap(pdfs.name, pdfs_tmp.name)
# Macroscopic Values
dh.run_kernel(getter_kernels[current_timestep.idx])
# Run the simulation
init()
for _ in range(100):
one_step()
# Evaluation
if gpu:
dh.to_cpu(velocity_field.name)
u = dh.gather_array(velocity_field.name)
# Equal to the steady-state velocity field up to numerical errors
assert_allclose(u, u_ref)
# Flow must be equal up to numerical error for all streaming patterns
global all_results
for key, prev_u in all_results.items():
if key[0] == stencil:
prev_pattern = key[1]
assert_allclose(
u,
prev_u,
err_msg=
f'Velocity field for {streaming_pattern} differed from {prev_pattern}!'
)
all_results[(stencil, streaming_pattern)] = u
def __init__(self, stencil, streaming_pattern, wall_boundary=None, target=Target.CPU):
if wall_boundary is None:
wall_boundary = NoSlip()
self.target = target
self.gpu = target in [Target.GPU]
# Stencil
self.stencil = stencil
self.q = stencil.Q
self.dim = stencil.D
# Streaming
self.streaming_pattern = streaming_pattern
self.inplace = is_inplace(self.streaming_pattern)
self.timesteps = get_timesteps(streaming_pattern)
self.zeroth_timestep = self.timesteps[0]
# Domain, Data Handling and PDF fields
self.pipe_length = 60
self.pipe_radius = 15
self.domain_size = (self.pipe_length, ) + (2 * self.pipe_radius,) * (self.dim - 1)
self.periodicity = (True, ) + (False, ) * (self.dim - 1)
self.force = (0.0001, ) + (0.0,) * (self.dim - 1)
self.dh = create_data_handling(domain_size=self.domain_size,
periodicity=self.periodicity, default_target=self.target)
self.pdfs = self.dh.add_array('pdfs', self.q)
if not self.inplace:
self.pdfs_tmp = self.dh.add_array_like('pdfs_tmp', self.pdfs.name)
# LBM Streaming and Collision
lbm_config = LBMConfig(stencil=stencil, method=Method.SRT, relaxation_rate=1.0,
force_model=ForceModel.GUO, force=self.force, streaming_pattern=streaming_pattern)
lbm_opt = LBMOptimisation(symbolic_field=self.pdfs)
config = CreateKernelConfig(target=self.target)
if not self.inplace:
lbm_opt = replace(lbm_opt, symbolic_temporary_field=self.pdfs_tmp)
self.lb_collision = create_lb_collision_rule(lbm_config=lbm_config, lbm_optimisation=lbm_opt)
self.lb_method = self.lb_collision.method
self.lb_kernels = []
for t in self.timesteps:
lbm_config = replace(lbm_config, timestep=t)
self.lb_kernels.append(create_lb_function(collision_rule=self.lb_collision,
lbm_config=lbm_config,
lbm_optimisation=lbm_opt,
config=config))
# Macroscopic Values
self.density = 1.0
self.density_field = self.dh.add_array('rho', 1)
u_x = 0.0
self.velocity = (u_x,) * self.dim
self.velocity_field = self.dh.add_array('u', self.dim)
setter = macroscopic_values_setter(
self.lb_method, self.density, self.velocity, self.pdfs,
streaming_pattern=self.streaming_pattern, previous_timestep=self.zeroth_timestep)
self.init_kernel = create_kernel(setter,
config=CreateKernelConfig(target=target, ghost_layers=1)).compile()
self.getter_kernels = []
for t in self.timesteps:
getter = macroscopic_values_getter(
self.lb_method, self.density_field, self.velocity_field, self.pdfs,
streaming_pattern=self.streaming_pattern, previous_timestep=t)
self.getter_kernels.append(create_kernel(getter,
config=CreateKernelConfig(target=target, ghost_layers=1)).compile())
# Periodicity
self.periodicity_handler = LBMPeriodicityHandling(
self.stencil, self.dh, self.pdfs.name, streaming_pattern=self.streaming_pattern)
# Boundary Handling
self.wall = wall_boundary
self.bh = LatticeBoltzmannBoundaryHandling(
self.lb_method, self.dh, self.pdfs.name,
streaming_pattern=self.streaming_pattern, target=self.target)
self.bh.set_boundary(boundary_obj=self.wall, mask_callback=self.mask_callback)
self.current_timestep = self.zeroth_timestep