def test_field_slice():
"""Tests (un)packing slices of a scalar field (from)to a buffer."""
fields = _generate_fields()
for d in ['N', 'S', 'NW', 'SW', 'TNW', 'B']:
for (src_arr, gpu_src_arr, gpu_dst_arr, gpu_buffer_arr) in fields:
# Extract slice from N direction of the field
slice_dir = direction_string_to_offset(d, dim=len(src_arr.shape))
pack_slice = get_slice_before_ghost_layer(slice_dir)
unpack_slice = get_ghost_region_slice(slice_dir)
src_field = Field.create_from_numpy_array("src_field",
src_arr[pack_slice])
dst_field = Field.create_from_numpy_array("dst_field",
src_arr[unpack_slice])
buffer = Field.create_generic("buffer",
spatial_dimensions=1,
field_type=FieldType.BUFFER,
dtype=src_arr.dtype)
pack_eqs = [Assignment(buffer.center(), src_field.center())]
pack_types = {
'src_field': gpu_src_arr.dtype,
'buffer': gpu_buffer_arr.dtype
}
pack_code = create_cuda_kernel(pack_eqs, type_info=pack_types)
pack_kernel = make_python_function(pack_code)
pack_kernel(buffer=gpu_buffer_arr,
src_field=gpu_src_arr[pack_slice])
# Unpack into ghost layer of dst_field in N direction
unpack_eqs = [Assignment(dst_field.center(), buffer.center())]
unpack_types = {
'dst_field': gpu_dst_arr.dtype,
'buffer': gpu_buffer_arr.dtype
}
unpack_code = create_cuda_kernel(unpack_eqs,
type_info=unpack_types)
unpack_kernel = make_python_function(unpack_code)
unpack_kernel(buffer=gpu_buffer_arr,
dst_field=gpu_dst_arr[unpack_slice])
dst_arr = gpu_dst_arr.get()
np.testing.assert_equal(src_arr[pack_slice], dst_arr[unpack_slice])
def test_extrapolation_outflow_initialization_by_copy():
stencil = LBStencil(Stencil.D2Q9)
domain_size = (1, 5)
streaming_pattern = 'esotwist'
zeroth_timestep = 'even'
pdf_acc = AccessPdfValues(stencil,
streaming_pattern=streaming_pattern,
timestep=zeroth_timestep,
streaming_dir='out')
dh = create_data_handling(domain_size, default_target=Target.CPU)
lb_method = create_lb_method(stencil=stencil)
pdf_field = dh.add_array('f', values_per_cell=stencil.Q)
dh.fill(pdf_field.name, np.nan, ghost_layers=True)
pdf_arr = dh.cpu_arrays[pdf_field.name]
bh = LatticeBoltzmannBoundaryHandling(lb_method,
dh,
pdf_field.name,
streaming_pattern=streaming_pattern,
target=Target.CPU)
for y in range(1, 6):
for j in range(stencil.Q):
pdf_acc.write_pdf(pdf_arr, (1, y), j, j)
normal_dir = (1, 0)
outflow = ExtrapolationOutflow(normal_dir,
lb_method,
streaming_pattern=streaming_pattern,
zeroth_timestep=zeroth_timestep)
boundary_slice = get_ghost_region_slice(normal_dir)
bh.set_boundary(outflow, boundary_slice)
bh.prepare()
blocks = list(dh.iterate())
index_list = blocks[0][
bh._index_array_name].boundary_object_to_index_list[outflow]
assert len(index_list) == 13
for entry in index_list:
direction = stencil[entry["dir"]]
inv_dir = stencil.index(inverse_direction(direction))
assert entry[f'pdf'] == inv_dir
assert entry[f'pdf_nd'] == inv_dir
def test_pdf_simple_extrapolation(stencil_enum, streaming_pattern):
stencil = LBStencil(stencil_enum)
# Field contains exactly one fluid cell
domain_size = (3, ) * stencil.D
for timestep in get_timesteps(streaming_pattern):
dh = create_data_handling(domain_size, default_target=Target.CPU)
lb_method = create_lb_method(lbm_config=LBMConfig(stencil=stencil))
pdf_field = dh.add_array('f', values_per_cell=stencil.Q)
dh.fill(pdf_field.name, np.nan, ghost_layers=True)
bh = LatticeBoltzmannBoundaryHandling(lb_method,
dh,
pdf_field.name,
streaming_pattern,
target=Target.CPU)
# Set up outflows in all directions
for normal_dir in stencil[1:]:
boundary_obj = SimpleExtrapolationOutflow(normal_dir, stencil)
boundary_slice = get_ghost_region_slice(normal_dir)
bh.set_boundary(boundary_obj, boundary_slice)
pdf_arr = dh.cpu_arrays[pdf_field.name]
# Set up the domain with artificial PDF values
# center = (1,) * dim
out_access = AccessPdfValues(stencil, streaming_pattern, timestep,
'out')
for cell in product(*(range(1, 4) for _ in range(stencil.D))):
for q in range(stencil.Q):
out_access.write_pdf(pdf_arr, cell, q, q)
# Do boundary handling
bh(prev_timestep=timestep)
# Check PDF values
in_access = AccessPdfValues(stencil, streaming_pattern,
timestep.next(), 'in')
# Inbound in center cell
for cell in product(*(range(1, 4) for _ in range(stencil.D))):
for q in range(stencil.Q):
f = in_access.read_pdf(pdf_arr, cell, q)
assert f == q
def test_pull_communication_slices(stencil):
stencil = LBStencil(stencil)
slices = get_communication_slices(
stencil, streaming_pattern='pull', prev_timestep=Timestep.BOTH, ghost_layers=1)
for i, d in enumerate(stencil):
if i == 0:
continue
for s in slices[d]:
if s[0][-1] == i:
src = s[0][:-1]
dst = s[1][:-1]
break
inner_slice = _fix_length_one_slices(get_slice_before_ghost_layer(d, ghost_layers=1))
inv_dir = (-e for e in d)
gl_slice = _fix_length_one_slices(get_ghost_region_slice(inv_dir, ghost_layers=1))
assert src == inner_slice
assert dst == gl_slice
def test_extrapolation_outflow_initialization_by_callback():
stencil = LBStencil(Stencil.D2Q9)
domain_size = (1, 5)
streaming_pattern = 'esotwist'
zeroth_timestep = 'even'
dh = create_data_handling(domain_size, default_target=Target.CPU)
lb_method = create_lb_method(stencil=stencil)
pdf_field = dh.add_array('f', values_per_cell=stencil.Q)
dh.fill(pdf_field.name, np.nan, ghost_layers=True)
bh = LatticeBoltzmannBoundaryHandling(lb_method,
dh,
pdf_field.name,
streaming_pattern=streaming_pattern,
target=Target.CPU)
normal_dir = (1, 0)
outflow = ExtrapolationOutflow(normal_direction=normal_dir,
lb_method=lb_method,
streaming_pattern=streaming_pattern,
zeroth_timestep=zeroth_timestep,
initial_density=lambda x, y: 1,
initial_velocity=lambda x, y: (0, 0))
boundary_slice = get_ghost_region_slice(normal_dir)
bh.set_boundary(outflow, boundary_slice)
bh.prepare()
weights = [w.evalf() for w in lb_method.weights]
blocks = list(dh.iterate())
index_list = blocks[0][
bh._index_array_name].boundary_object_to_index_list[outflow]
assert len(index_list) == 13
for entry in index_list:
direction = stencil[entry["dir"]]
inv_dir = stencil.index(inverse_direction(direction))
assert entry[f'pdf_nd'] == weights[inv_dir]