Commit 06aeddba authored by Frederik Hennig's avatar Frederik Hennig
Browse files

Completed advanced periodicity handling and added fully periodic test scenario

parent ef03d2e6
Pipeline #27101 failed with stage
in 26 minutes and 44 seconds
......@@ -2,7 +2,9 @@ from .boundaryindexing import AdvancedStreamingBoundaryIndexing
from .boundaryconditions import FlexibleBoundary, FlexibleNoSlip
from .boundaryhandling import FlexibleLBMBoundaryHandling, \
from .communication import get_communication_slices, PeriodicityHandling
__all__ = ['AdvancedStreamingBoundaryIndexing', 'FlexibleBoundary',
'FlexibleNoSlip', 'create_advanced_streaming_boundary_kernel',
'get_communication_slices', 'PeriodicityHandling']
from pystencils import Field
from pystencils.slicing import shift_slice, get_slice_before_ghost_layer
from lbmpy.advanced_streaming.utility import get_accessor, numeric_index, numeric_offsets
from lbmpy.advanced_streaming.utility import is_inplace, get_accessor, numeric_index, numeric_offsets
from pystencils.datahandling import SerialDataHandling
from itertools import chain
def cut_slice_in_direction(slices, direction):
def trim_slice_in_direction(slices, direction):
assert len(slices) == len(direction)
result = []
for s, d in zip(slices, direction):
if isinstance(s, int):
start = s.start + 1 if d == -1 else s.start
stop = s.stop - 1 if d == 1 else s.stop
result.append(slice(start, stop, s.step))
......@@ -32,37 +37,43 @@ def _get_neighbour_transform(direction, ghost_layers):
def _fix_length_one_slices(slices):
if isinstance(slices, slice):
if slices.stop is None:
return slices
"""Slices of length one are replaced by their start value for correct periodic shifting"""
if isinstance(slices, int):
return slices
elif isinstance(slices, slice):
if slices.stop is not None and abs(slices.start - slices.stop) == 1:
return slices.start
elif slices.stop is None and slices.start == -1:
return -1 # [-1:] also has length one
return slice(slices.start, None if abs(slices.start - slices.stop) == 1 else slices.stop)
return tuple(_fix_length_one_slices(s) for s in slices)
return slices
return tuple(_fix_length_one_slices(s) for s in slices)
def get_communication_slices(stencil, streaming_pattern='pull', after_timestep='both', ghost_layers=1):
def get_communication_slices(stencil, comm_stencil=None, streaming_pattern='pull', after_timestep='both', ghost_layers=1):
Return the source and destination slices for periodicity handling or communication between
blocks. This function returns a dictionary which contains a list of tuples
(idx, src_slice, dst_slice) for each stencil direction. Here, idx is an index to the pdf field,
src_slice the source region of the current block, and dst_slice the destination region in the
adjacent block.
Return the source and destination slices for periodicity handling or communication between blocks.
:param lb_method: The lattice boltzmann method to be used.
:param stencil: The stencil used by the LB method.
:param comm_stencil: The stencil defining the communication directions. If None, it will be set to stencil.
:param streaming_pattern: The streaming pattern.
:param after_timestep: Timestep after which communication is run; either 'even', 'odd' or 'both'.
:param ghost_layers: Number of ghost layers in each direction.
if comm_stencil is None:
comm_stencil = stencil
pdfs = Field.create_generic('pdfs', spatial_dimensions=len(stencil[0]), index_shape=(len(stencil),))
write_accesses = get_accessor(streaming_pattern, after_timestep).write(pdfs, stencil)
all_slices = dict()
slices_per_comm_direction = dict()
for comm_dir in stencil:
for comm_dir in comm_stencil:
if all(d == 0 for d in comm_dir):
slices_for_dir = dict()
slices_for_dir = []
for streaming_dir in set(extend_dir(comm_dir)) & set(stencil):
d = stencil.index(streaming_dir)
......@@ -72,18 +83,74 @@ def get_communication_slices(stencil, streaming_pattern='pull', after_timestep='
tangential_dir = tuple(s - c for s, c in zip(streaming_dir, comm_dir))
origin_slice = get_slice_before_ghost_layer(comm_dir, ghost_layers=ghost_layers, thickness=1)
origin_slice = _fix_length_one_slices(origin_slice)
src_slice = shift_slice(cut_slice_in_direction(origin_slice, tangential_dir), write_offsets)
src_slice = shift_slice(trim_slice_in_direction(origin_slice, tangential_dir), write_offsets)
neighbour_transform = _get_neighbour_transform(comm_dir, ghost_layers)
dst_slice = shift_slice(src_slice, neighbour_transform)
slices_for_dir[write_index] = ((src_slice, dst_slice))
src_slice = src_slice + (write_index, )
dst_slice = dst_slice + (write_index, )
slices_for_dir.append((src_slice, dst_slice))
all_slices[comm_dir] = slices_for_dir
return all_slices
slices_per_comm_direction[comm_dir] = slices_for_dir
return slices_per_comm_direction
class PeriodicityHandling:
def __init__(self, lb_method, streaming_pattern, data_handling, pdf_field_name, periodicities):
def __init__(self, stencil, data_handling, pdf_field_name,
streaming_pattern='pull', zeroth_timestep='both',
ghost_layers=1, gpu=False):
if not isinstance(data_handling, SerialDataHandling):
raise ValueError('Only single node data handling is supported!')
self.stencil = stencil
self.dh = data_handling
self.pdf_field_name = pdf_field_name
periodicity = data_handling.periodicity
self.inplace_pattern = is_inplace(streaming_pattern)
self.gpu = gpu
def is_copy_direction(direction):
for d, p in zip(direction, periodicity):
if d != 0 and not p:
return False
return True
copy_directions = tuple(filter(is_copy_direction, stencil[1:]))
if self.inplace_pattern:
self.comm_slices = dict()
for timestep in ['even', 'odd']:
slices_per_comm_dir = get_communication_slices(stencil=stencil,
self.comm_slices[timestep] = list(chain.from_iterable(v for k, v in slices_per_comm_dir.items()))
slices_per_comm_dir = get_communication_slices(stencil=stencil,
self.comm_slices = list(chain.from_iterable(v for k, v in slices_per_comm_dir.items()))
def __call__(self, timestep_modulus='both'):
if self.gpu:
def _periodicity_handling_cpu(self, timestep):
arr = self.dh.cpu_arrays[self.pdf_field_name]
if timestep == 'both':
comm_slices = self.comm_slices
comm_slices = self.comm_slices[timestep]
for src, dst in comm_slices:
arr[dst] = arr[src]
def _periodicity_handling_gpu(self, timestep):
raise NotImplementedError()
\ No newline at end of file
......@@ -39,6 +39,11 @@ def get_accessor(streaming_pattern, timestep) -> PdfFieldAccessor:
return odd_accessors[streaming_pattern]
def is_inplace(streaming_pattern):
if streaming_pattern not in streaming_patterns:
raise ValueError('Invalid streaming pattern', streaming_pattern)
return streaming_pattern in ['aa', 'esotwist']
def numeric_offsets(field_access: ps.Field.Access):
return tuple(int(o) for o in field_access.offsets)
......@@ -11,24 +11,48 @@ import pytest
@pytest.mark.parametrize('timestep', ['even', 'odd'])
def test_slices_not_empty(stencil, streaming_pattern, timestep):
stencil = get_stencil(stencil)
arr = np.zeros( (4,) * len(stencil[0]) )
slices = get_communication_slices(stencil, streaming_pattern, timestep, 1)
for _, slices_dict in slices.items():
for _, comm_slices in slices_dict.items():
assert all(s != 0 for s in arr[comm_slices[0]].shape)
assert all(s != 0 for s in arr[comm_slices[1]].shape)
dim = len(stencil[0])
q = len(stencil)
arr = np.zeros( (4,) * dim + (q,) )
slices = get_communication_slices(stencil, streaming_pattern=streaming_pattern, after_timestep=timestep, ghost_layers=1)
for _, slices_list in slices.items():
for src, dst in slices_list:
assert all(s != 0 for s in arr[src].shape)
assert all(s != 0 for s in arr[dst].shape)
@pytest.mark.parametrize('stencil', ['D2Q9', 'D3Q19', 'D3Q27'])
@pytest.mark.parametrize('streaming_pattern', streaming_patterns)
@pytest.mark.parametrize('timestep', ['even', 'odd'])
def test_src_dst_same_shape(stencil, streaming_pattern, timestep):
stencil = get_stencil(stencil)
dim = len(stencil[0])
q = len(stencil)
arr = np.zeros( (4,) * dim + (q,) )
slices = get_communication_slices(stencil, streaming_pattern=streaming_pattern, after_timestep=timestep, ghost_layers=1)
for _, slices_list in slices.items():
for src, dst in slices_list:
src_shape = arr[src].shape
dst_shape = arr[dst].shape
assert src_shape == dst_shape
@pytest.mark.parametrize('stencil', ['D2Q9', 'D3Q19', 'D3Q27'])
def test_pull_communication_slices(stencil):
stencil = get_stencil(stencil)
slices = get_communication_slices(stencil, 'pull', 'both', 1)
slices = get_communication_slices(
stencil, streaming_pattern='pull', after_timestep='both', ghost_layers=1)
for i, d in enumerate(stencil):
if i == 0:
src, dst = slices[d][i]
for s in slices[d]:
if s[0][-1] == i:
src = s[0][:-1]
dst = s[1][:-1]
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))
This diff is collapsed.
import numpy as np
import sympy as sp
from pystencils.datahandling import create_data_handling
from pystencils import create_kernel
from pystencils.plot import scalar_field, vector_field, vector_field_magnitude
from lbmpy.creationfunctions import create_lb_collision_rule, create_lb_function
from lbmpy.macroscopic_value_kernels import flexible_macroscopic_values_getter, flexible_macroscopic_values_setter
from lbmpy.stencils import get_stencil
from lbmpy.advanced_streaming import PeriodicityHandling
from lbmpy.advanced_streaming.utility import is_inplace, streaming_patterns
import pytest
from numpy.testing import assert_allclose, assert_array_equal
all_results = dict()
@pytest.mark.parametrize('stencil', ['D2Q9', 'D3Q19', 'D3Q27'])
@pytest.mark.parametrize('streaming_pattern', streaming_patterns)
def test_fully_periodic_flow(stencil, streaming_pattern):
# Stencil
stencil = get_stencil(stencil)
q = len(stencil)
dim = len(stencil[0])
# Streaming
inplace = is_inplace(streaming_pattern)
timesteps = ['even', 'odd'] if inplace else ['both']
zeroth_timestep = timesteps[0]
# Data Handling and PDF fields
domain_size = (30,) * dim
periodicity = (True,) * dim
dh = create_data_handling(domain_size=domain_size, periodicity=periodicity)
pdfs = dh.add_array('pdfs', q)
if not inplace:
pdfs_tmp = dh.add_array_like('pdfs_tmp',
# LBM Streaming and Collision
method_params = {
'stencil': stencil,
'method': 'srt',
'relaxation_rate': 1.0
optimization = {
'symbolic_field': pdfs,
'target': 'cpu'
if not inplace:
optimization['symbolic_temporary_field'] = pdfs_tmp
lb_collision = create_lb_collision_rule(optimization=optimization, **method_params)
lb_method = lb_collision.method
lb_kernels = []
if inplace:
kernel_type=streaming_pattern + '_even',
kernel_type=streaming_pattern + '_odd',
if streaming_pattern == 'pull':
kernel_type = 'stream_pull_collide'
elif streaming_pattern == 'push':
kernel_type = 'collide_stream_push'
# Macroscopic Values
density = 1.0
density_field = dh.add_array('rho', 1)
u_x = 0.01
velocity = (u_x,) * dim
velocity_field = dh.add_array('u', dim)
u_ref = np.full(domain_size + (dim,), u_x)
setter = flexible_macroscopic_values_setter(
lb_method, density, velocity, pdfs,
streaming_pattern=streaming_pattern, previous_timestep=zeroth_timestep)
setter_kernel = create_kernel(setter, ghost_layers=1).compile()
getter_kernels = []
for t in timesteps:
getter = flexible_macroscopic_values_getter(
lb_method, density_field, velocity_field, pdfs,
streaming_pattern=streaming_pattern, previous_timestep=t)
getter_kernels.append(create_kernel(getter, ghost_layers=1).compile())
# Periodicity
periodicity_handler = PeriodicityHandling(
stencil, dh,,
streaming_pattern=streaming_pattern, zeroth_timestep=zeroth_timestep)
# Initialization and Timestep
t_modulus = 0
def init():
global t_modulus
t_modulus = 0
def one_step():
global t_modulus
# Periodicty
# Macroscopic Values
# Here, the next time step begins
t_modulus = (t_modulus + 1) % len(timesteps)
# LBM Step
# Field Swaps
if not inplace:
# Run the simulation
for _ in range(100):
# Evaluation
u = dh.gather_array(
# Equal to the steady-state velocity field up to numerical errors
assert_allclose(u, u_ref)
# Exactly equal to other streaming patterns!
global all_results
for prev_pattern, prev_u in all_results.items():
u, prev_u, err_msg=f'Velocity field for {streaming_pattern} differed from {prev_pattern}!')
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