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Commit dd1cbd09 authored by Frederik Hennig's avatar Frederik Hennig
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replaced boundary handling by new implementation

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lbmpy/advanced_streaming/__init__.py
View file @ dd1cbd09
from .indexing import BetweenTimestepsIndexing
from .boundaryconditions import FlexibleBoundary, FlexibleNoSlip
from .boundaryhandling import FlexibleLBMBoundaryHandling, \
create_advanced_streaming_boundary_kernel
from .communication import get_communication_slices, PeriodicityHandling
from .utility import Timestep, get_accessor
__all__ = ['BetweenTimestepsIndexing', 'FlexibleBoundary',
'FlexibleNoSlip', 'create_advanced_streaming_boundary_kernel',
'FlexibleLBMBoundaryHandling',
__all__ = ['BetweenTimestepsIndexing',
'get_communication_slices', 'PeriodicityHandling',
'Timestep', 'get_accessor']
lbmpy/advanced_streaming/boundaryconditions.py deleted 100644 → 0
View file @ c91bf2ac
import sympy as sp
from pystencils import Assignment, Field
from lbmpy.boundaries.boundaryhandling import LbmWeightInfo
from pystencils.data_types import create_type
from pystencils.sympyextensions import get_symmetric_part
from lbmpy.simplificationfactory import create_simplification_strategy
from lbmpy.advanced_streaming.indexing import NeighbourOffsetArraysForStencil
class FlexibleBoundary:
"""Base class for all boundary classes that use the AdvancedStreamingBoundaryIndexing"""
inner_or_boundary = True
single_link = False
def __init__(self, name=None):
self._name = name
def __call__(self, f_out, f_in, dir_symbol, inv_dir, lb_method, index_field):
"""
This function defines the boundary behavior and must therefore be implemented by all boundaries.
The boundary is defined through a list of sympy equations from which a boundary kernel is generated.
:param f_out: a pystencils field acting as a proxy to access the populations streaming out of the current
cell, i.e. the post-collision PDFs of the previous LBM step
:param f_in: a pystencils field acting as a proxy to access the populations streaming into the current
cell, i.e. the pre-collision PDFs for the next LBM step
:param dir_symbol: a sympy symbol that can be used as an index to f_out and f_in. It describes the direction
pointing from the fluid to the boundary cell.
:param inv_dir: an indexed sympy symbol which describes the inversion of a direction index. It can be used in
the indices of f_out and f_in for retrieving the PDF of the inverse direction.
:param lb_method: an instance of the LB method used. Use this to adapt the boundary to the method
(e.g. compressibility)
:param index_field: the boundary index field that can be used to retrieve and update boundary data
:return: list of pystencils assignments, or pystencils.AssignmentCollection
"""
raise NotImplementedError("Boundary class has to overwrite __call__")
@property
def additional_data(self):
"""Return a list of (name, type) tuples for additional data items required in this boundary
These data items can either be initialized in separate kernel see additional_data_kernel_init or by
Python callbacks - see additional_data_callback """
return []
@property
def additional_data_init_callback(self):
"""Return a callback function called with a boundary data setter object and returning a dict of
data-name to data for each element that should be initialized"""
return None
def get_additional_code_nodes(self, lb_method):
"""Return a list of code nodes that will be added in the generated code before the index field loop."""
return []
@property
def name(self):
if self._name:
return self._name
else:
return type(self).__name__
@name.setter
def name(self, new_value):
self._name = new_value
# end class FlexibleBoundary
class FlexibleNoSlip(FlexibleBoundary):
def __init__(self, name=None):
"""Set an optional name here, to mark boundaries, for example for force evaluations"""
super(FlexibleNoSlip, self).__init__(name)
"""
No-Slip, (half-way) simple bounce back boundary condition, enforcing zero velocity at obstacle.
Extended for use with any streaming pattern.
"""
def __call__(self, f_out, f_in, dir_symbol, inv_dir, lb_method, index_field):
return Assignment(f_in(inv_dir[dir_symbol]), f_out(dir_symbol))
def __hash__(self):
return hash(self.name)
def __eq__(self, other):
if not isinstance(other, FlexibleNoSlip):
return False
return self.name == other.name
# end class FlexibleNoSlip
class FlexibleUBB(FlexibleBoundary):
"""Velocity bounce back boundary condition, enforcing specified velocity at obstacle"""
def __init__(self, velocity, adapt_velocity_to_force=False, dim=None, name=None):
"""
Args:
velocity: can either be a constant, an access into a field, or a callback function.
The callback functions gets a numpy record array with members, 'x','y','z', 'dir' (direction)
and 'velocity' which has to be set to the desired velocity of the corresponding link
adapt_velocity_to_force:
"""
super(FlexibleUBB, self).__init__(name)
self._velocity = velocity
self._adaptVelocityToForce = adapt_velocity_to_force
if callable(self._velocity) and not dim:
raise ValueError("When using a velocity callback the dimension has to be specified with the dim parameter")
elif not callable(self._velocity):
dim = len(velocity)
self.dim = dim
@property
def additional_data(self):
if callable(self._velocity):
return [('vel_%d' % (i,), create_type("double")) for i in range(self.dim)]
else:
return []
@property
def additional_data_init_callback(self):
if callable(self._velocity):
return self._velocity
@property
def get_additional_code_nodes(self, lb_method):
return [LbmWeightInfo(lb_method), NeighbourOffsetArraysForStencil(lb_method.stencil)]
def __call__(self, f_out, f_in, dir_symbol, inv_dir, lb_method, index_field):
vel_from_idx_field = callable(self._velocity)
vel = [index_field(f'vel_{i}') for i in range(self.dim)] if vel_from_idx_field else self._velocity
direction = dir_symbol
assert self.dim == lb_method.dim, f"Dimension of UBB ({self.dim}) does not match dimension of method ({lb_method.dim})"
neighbor_offset = NeighbourOffsetArraysForStencil.symbolic_neighbour_offset_from_dir(
direction, lb_method.dim)
velocity = tuple(v_i.get_shifted(*neighbor_offset)
if isinstance(v_i, Field.Access) and not vel_from_idx_field
else v_i
for v_i in vel)
if self._adaptVelocityToForce:
cqc = lb_method.conserved_quantity_computation
shifted_vel_eqs = cqc.equilibrium_input_equations_from_init_values(velocity=velocity)
velocity = [eq.rhs for eq in shifted_vel_eqs.new_filtered(cqc.first_order_moment_symbols).main_assignments]
c_s_sq = sp.Rational(1, 3)
weight_of_direction = LbmWeightInfo.weight_of_direction
vel_term = 2 / c_s_sq \
* sum([d_i * v_i for d_i, v_i in zip(neighbor_offset, velocity)]) \
* weight_of_direction(direction)
# Better alternative: in conserved value computation
# rename what is currently called density to "virtual_density"
# provide a new quantity density, which is constant in case of incompressible models
if not lb_method.conserved_quantity_computation.zero_centered_pdfs:
cqc = lb_method.conserved_quantity_computation
density_symbol = sp.Symbol("rho")
pdf_field_accesses = [f_out(i) for i in range(len(lb_method.stencil))]
density_equations = cqc.output_equations_from_pdfs(pdf_field_accesses, {'density': density_symbol})
density_symbol = lb_method.conserved_quantity_computation.defined_symbols()['density']
result = density_equations.all_assignments
result += [Assignment(f_in(inv_dir[direction]),
f_out(direction) - vel_term * density_symbol)]
return result
else:
return [Assignment(f_in(inv_dir[direction]),
f_out(direction) - vel_term)]
lbmpy/advanced_streaming/boundaryhandling.py deleted 100644 → 0
View file @ c91bf2ac
import numpy as np
from lbmpy.advanced_streaming.indexing import BetweenTimestepsIndexing
from lbmpy.advanced_streaming.utility import is_inplace, Timestep, AccessPdfValues
from pystencils import Field, Assignment, create_indexed_kernel
from pystencils.stencil import inverse_direction
from pystencils.boundaries import BoundaryHandling
from pystencils.boundaries.createindexlist import numpy_data_type_for_boundary_object
class FlexibleLBMBoundaryHandling(BoundaryHandling):
"""
Enables boundary handling for LBM simulations with advanced streaming patterns.
For the in-place patterns AA and EsoTwist, two kernels are generated for a boundary
object and the right one selected depending on the time step.
"""
def __init__(self, lb_method, data_handling, pdf_field_name, streaming_pattern='pull',
name="boundary_handling", flag_interface=None, 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(FlexibleLBMBoundaryHandling, self).__init__(data_handling, pdf_field_name, lb_method.stencil,
name, flag_interface, target, openmp)
# ------------------------- Overridden methods of pystencils.BoundaryHandling -------------------------
@property
def prev_timestep(self):
return self._prev_timestep
def __call__(self, prev_timestep=Timestep.BOTH, **kwargs):
self._prev_timestep = prev_timestep
super(FlexibleLBMBoundaryHandling, self).__call__(**kwargs)
self._prev_timestep = None
def add_fixed_steps(self, fixed_loop, **kwargs):
raise NotImplementedError("Adding to fixed loop is not supported by FlexibleLBMBoundaryHandling")
def _add_boundary(self, boundary_obj, flag=None):
if self._inplace:
return self._add_flexible_boundary(boundary_obj, flag)
else:
return super(FlexibleLBMBoundaryHandling, self)._add_boundary(boundary_obj, flag)
def _add_flexible_boundary(self, boundary_obj, flag=None):
if boundary_obj not in self._boundary_object_to_boundary_info:
sym_index_field = Field.create_generic('indexField', spatial_dimensions=1,
dtype=numpy_data_type_for_boundary_object(boundary_obj, self.dim))
kernels = [self._create_boundary_kernel(
self._data_handling.fields[self._field_name], sym_index_field, boundary_obj, Timestep.EVEN).compile(),
self._create_boundary_kernel(
self._data_handling.fields[self._field_name], sym_index_field, boundary_obj, Timestep.ODD).compile()]
if flag is None:
flag = self.flag_interface.reserve_next_flag()
boundary_info = self.InplaceStreamingBoundaryInfo(self, boundary_obj, flag, kernels)
self._boundary_object_to_boundary_info[boundary_obj] = boundary_info
return self._boundary_object_to_boundary_info[boundary_obj].flag
def _create_boundary_kernel(self, symbolic_field, symbolic_index_field, boundary_obj, prev_timestep=Timestep.BOTH):
return create_advanced_streaming_boundary_kernel(
symbolic_field, symbolic_index_field, self._lb_method, boundary_obj,
prev_timestep=prev_timestep, streaming_pattern=self._streaming_pattern,
target=self._target, openmp=self._openmp)
class InplaceStreamingBoundaryInfo(object):
@property
def kernel(self):
prev_timestep = self._boundary_handling.prev_timestep
if prev_timestep is None:
raise Exception(
"The boundary kernel property was accessed while "
+ "there was no boundary handling in progress.")
return self._kernels[prev_timestep]
def __init__(self, boundary_handling, boundary_obj, flag, kernels):
self._boundary_handling = boundary_handling
self.boundary_object = boundary_obj
self.flag = flag
self._kernels = kernels
# end class InplaceStreamingBoundaryInfo
# ------------------------------ Force On Boundary ------------------------------------------------------------
def force_on_boundary(self, boundary_obj, prev_timestep=Timestep.BOTH):
from lbmpy.advanced_streaming import FlexibleNoSlip
if isinstance(boundary_obj, FlexibleNoSlip):
return self._force_on_no_slip(boundary_obj, prev_timestep)
else:
self.__call__()
return self._force_on_boundary(boundary_obj, prev_timestep)
def _force_on_no_slip(self, boundary_obj, prev_timestep):
dh = self._data_handling
ff_ghost_layers = dh.ghost_layers_of_field(self.flag_interface.flag_field_name)
method = self._lb_method
stencil = np.array(method.stencil)
result = np.zeros(self.dim)
for b in dh.iterate(ghost_layers=ff_ghost_layers):
obj_to_ind_list = b[self._index_array_name].boundary_object_to_index_list
pdf_array = b[self._field_name]
if boundary_obj in obj_to_ind_list:
ind_arr = obj_to_ind_list[boundary_obj]
acc = AccessPdfValues(dh.fields[self._field_name], self._lb_method.stencil,
streaming_pattern=self._streaming_pattern, timestep=prev_timestep,
streaming_dir='out')
values = 2 * acc.collect_from_index_list(pdf_array, ind_arr)
forces = stencil[ind_arr['dir']] * values[:, np.newaxis]
result += forces.sum(axis=0)
return dh.reduce_float_sequence(list(result), 'sum')
def _force_on_boundary(self, boundary_obj, prev_timestep):
dh = self._data_handling
ff_ghost_layers = dh.ghost_layers_of_field(self.flag_interface.flag_field_name)
method = self._lb_method
stencil = np.array(method.stencil)
result = np.zeros(self.dim)
for b in dh.iterate(ghost_layers=ff_ghost_layers):
obj_to_ind_list = b[self._index_array_name].boundary_object_to_index_list
pdf_array = b[self._field_name]
if boundary_obj in obj_to_ind_list:
ind_arr = obj_to_ind_list[boundary_obj]
acc_out = AccessPdfValues(dh.fields[self._field_name], self._lb_method.stencil,
streaming_pattern=self._streaming_pattern, timestep=prev_timestep,
streaming_dir='out')
acc_in = AccessPdfValues(dh.fields[self._field_name], self._lb_method.stencil,
streaming_pattern=self._streaming_pattern, timestep=prev_timestep.next(),
streaming_dir='in')
acc_fluid = acc_out if boundary_obj.inner_or_boundary else acc_in
acc_boundary = acc_in if boundary_obj.inner_or_boundary else acc_out
fluid_values = acc_fluid.collect_from_index_list(pdf_array, ind_arr)
boundary_values = acc_boundary.collect_from_index_list(pdf_array, ind_arr)
values = fluid_values + boundary_values
forces = stencil[ind_arr['dir']] * values[:, np.newaxis]
result += forces.sum(axis=0)
return dh.reduce_float_sequence(list(result), 'sum')
# end class FlexibleLBMBoundaryHandling
def create_advanced_streaming_boundary_kernel(pdf_field, index_field, lb_method, boundary_functor,
prev_timestep=Timestep.BOTH, streaming_pattern='pull',
target='cpu', openmp=True):
index_dtype = index_field.dtype.numpy_dtype.fields['dir'][0]
offsets_dtype = index_field.dtype.numpy_dtype.fields['x'][0]
indexing = BetweenTimestepsIndexing(
pdf_field, lb_method.stencil, prev_timestep, streaming_pattern, index_dtype, offsets_dtype)
f_out, f_in = indexing.proxy_fields
dir_symbol = indexing.dir_symbol
inv_dir = indexing.inverse_dir_symbol
boundary_assignments = boundary_functor(f_out, f_in, dir_symbol, inv_dir, lb_method, index_field)
boundary_assignments = indexing.substitute_proxies(boundary_assignments)
# Code Elements inside the loop
elements = [Assignment(dir_symbol, index_field[0]('dir'))]
elements += boundary_assignments.all_assignments
kernel = create_indexed_kernel(elements, [index_field], target=target, cpu_openmp=openmp)
# Code Elements ahead of the loop
index_arrs_node = indexing.create_code_node()
for node in boundary_functor.get_additional_code_nodes(lb_method)[::-1]:
kernel.body.insert_front(node)
kernel.body.insert_front(index_arrs_node)
return kernel
lbmpy/boundaries/boundaryconditions.py
View file @ dd1cbd09
import sympy as sp
from lbmpy.boundaries.boundaryhandling import BoundaryOffsetInfo, LbmWeightInfo
from lbmpy.simplificationfactory import create_simplification_strategy
from pystencils import Assignment, Field
from lbmpy.boundaries.boundaryhandling import LbmWeightInfo
from pystencils.data_types import create_type
from pystencils.sympyextensions import get_symmetric_part
from lbmpy.simplificationfactory import create_simplification_strategy
from lbmpy.advanced_streaming.indexing import NeighbourOffsetArraysForStencil
class Boundary:
"""Base class all boundaries should derive from"""
"""Base class for all boundary classes that use the AdvancedStreamingBoundaryIndexing"""
inner_or_boundary = True
single_link = False
......@@ -16,23 +16,25 @@ class Boundary:
def __init__(self, name=None):
self._name = name
def __call__(self, pdf_field, direction_symbol, lb_method, index_field):
def __call__(self, f_out, f_in, dir_symbol, inv_dir, lb_method, index_field):
"""
This function defines the boundary behavior and must therefore be implemented by all boundaries.
Here the boundary is defined as a list of sympy equations, from which a boundary kernel is generated.
Args:
pdf_field: pystencils field describing the pdf. The current cell is cell next to the boundary,
which is influenced by the boundary cell i.e. has a link from the boundary cell to
itself.
direction_symbol: a sympy symbol that can be used as index to the pdf_field. It describes
the direction pointing from the fluid to the boundary cell
lb_method: an instance of the LB method used. Use this to adapt the boundary to the method
(e.g. compressibility)
index_field: the boundary index field that can be used to retrieve and update boundary data
Returns:
:return: list of sympy equations
The boundary is defined through a list of sympy equations from which a boundary kernel is generated.
:param f_out: a pystencils field acting as a proxy to access the populations streaming out of the current
cell, i.e. the post-collision PDFs of the previous LBM step
:param f_in: a pystencils field acting as a proxy to access the populations streaming into the current
cell, i.e. the pre-collision PDFs for the next LBM step
:param dir_symbol: a sympy symbol that can be used as an index to f_out and f_in. It describes the direction
pointing from the fluid to the boundary cell.
:param inv_dir: an indexed sympy symbol which describes the inversion of a direction index. It can be used in
the indices of f_out and f_in for retrieving the PDF of the inverse direction.
:param lb_method: an instance of the LB method used. Use this to adapt the boundary to the method
(e.g. compressibility)
:param index_field: the boundary index field that can be used to retrieve and update boundary data
:return: list of pystencils assignments, or pystencils.AssignmentCollection
"""
raise NotImplementedError("Boundary class has to overwrite __call__")
......@@ -49,6 +51,10 @@ class Boundary:
data-name to data for each element that should be initialized"""
return None
def get_additional_code_nodes(self, lb_method):
"""Return a list of code nodes that will be added in the generated code before the index field loop."""
return []
@property
def name(self):
if self._name:
......@@ -60,6 +66,8 @@ class Boundary:
def name(self, new_value):
self._name = new_value
# end class Boundary
class NoSlip(Boundary):
......@@ -67,14 +75,15 @@ class NoSlip(Boundary):
"""Set an optional name here, to mark boundaries, for example for force evaluations"""
super(NoSlip, self).__init__(name)
"""No-Slip, (half-way) simple bounce back boundary condition, enforcing zero velocity at obstacle"""
def __call__(self, pdf_field, direction_symbol, lb_method, **kwargs):
neighbor = BoundaryOffsetInfo.offset_from_dir(direction_symbol, lb_method.dim)
inverse_dir = BoundaryOffsetInfo.inv_dir(direction_symbol)
return [Assignment(pdf_field[neighbor](inverse_dir), pdf_field(direction_symbol))]
"""
No-Slip, (half-way) simple bounce back boundary condition, enforcing zero velocity at obstacle.
Extended for use with any streaming pattern.
"""
def __call__(self, f_out, f_in, dir_symbol, inv_dir, lb_method, index_field):
return Assignment(f_in(inv_dir[dir_symbol]), f_out(dir_symbol))
def __hash__(self):
# All boundaries of these class behave equal -> should also be equal (as long as name is equal)
return hash(self.name)
def __eq__(self, other):
......@@ -82,6 +91,8 @@ class NoSlip(Boundary):
return False
return self.name == other.name
# end class NoSlip
class UBB(Boundary):
"""Velocity bounce back boundary condition, enforcing specified velocity at obstacle"""
......@@ -115,18 +126,23 @@ class UBB(Boundary):
if callable(self._velocity):
return self._velocity
def __call__(self, pdf_field, direction_symbol, lb_method, index_field, **kwargs):
def get_additional_code_nodes(self, lb_method):
return [LbmWeightInfo(lb_method), NeighbourOffsetArraysForStencil(lb_method.stencil)]
def __call__(self, f_out, f_in, dir_symbol, inv_dir, lb_method, index_field):
vel_from_idx_field = callable(self._velocity)
vel = [index_field('vel_%d' % (i,)) for i in range(self.dim)] if vel_from_idx_field else self._velocity
direction = direction_symbol
vel = [index_field(f'vel_{i}') for i in range(self.dim)] if vel_from_idx_field else self._velocity
direction = dir_symbol
assert self.dim == lb_method.dim, "Dimension of UBB (%d) does not match dimension of method (%d)" \
% (self.dim, lb_method.dim)
assert self.dim == lb_method.dim, f"Dimension of UBB ({self.dim}) does not match dimension of method ({lb_method.dim})"
neighbor = BoundaryOffsetInfo.offset_from_dir(direction, lb_method.dim)
inverse_dir = BoundaryOffsetInfo.inv_dir(direction)
neighbor_offset = NeighbourOffsetArraysForStencil.symbolic_neighbour_offset_from_dir(
direction, lb_method.dim)
velocity = tuple(v_i.get_shifted(*neighbor) if isinstance(v_i, Field.Access) and not vel_from_idx_field else v_i
velocity = tuple(v_i.get_shifted(*neighbor_offset)
if isinstance(v_i, Field.Access) and not vel_from_idx_field
else v_i
for v_i in vel)
if self._adaptVelocityToForce:
......@@ -136,8 +152,9 @@ class UBB(Boundary):
c_s_sq = sp.Rational(1, 3)
weight_of_direction = LbmWeightInfo.weight_of_direction
vel_term = 2 / c_s_sq * sum([d_i * v_i
for d_i, v_i in zip(neighbor, velocity)]) * weight_of_direction(direction)
vel_term = 2 / c_s_sq \
* sum([d_i * v_i for d_i, v_i in zip(neighbor_offset, velocity)]) \
* weight_of_direction(direction)
# Better alternative: in conserved value computation
# rename what is currently called density to "virtual_density"
......@@ -145,21 +162,23 @@ class UBB(Boundary):
if not lb_method.conserved_quantity_computation.zero_centered_pdfs:
cqc = lb_method.conserved_quantity_computation
density_symbol = sp.Symbol("rho")
pdf_field_accesses = [pdf_field(i) for i in range(len(lb_method.stencil))]
pdf_field_accesses = [f_out(i) for i in range(len(lb_method.stencil))]
density_equations = cqc.output_equations_from_pdfs(pdf_field_accesses, {'density': density_symbol})
density_symbol = lb_method.conserved_quantity_computation.defined_symbols()['density']
result = density_equations.all_assignments
result += [Assignment(pdf_field[neighbor](inverse_dir),
pdf_field(direction) - vel_term * density_symbol)]
result += [Assignment(f_in(inv_dir[direction]),
f_out(direction) - vel_term * density_symbol)]
return result
else:
return [Assignment(pdf_field[neighbor](inverse_dir),
pdf_field(direction) - vel_term)]
return [Assignment(f_in(inv_dir[direction]),
f_out(direction) - vel_term)]
# end class UBB
# TODO
class FixedDensity(Boundary):
def __init__(self, density, name=None):
raise NotImplementedError() # not yet operable
if name is None:
name = "Fixed Density " + str(density)
super(FixedDensity, self).__init__(name)
......@@ -208,6 +227,7 @@ class FixedDensity(Boundary):
class NeumannByCopy(Boundary):
def __call__(self, pdf_field, direction_symbol, lb_method, **kwargs):
raise NotImplementedError() # not yet operable
neighbor = BoundaryOffsetInfo.offset_from_dir(direction_symbol, lb_method.dim)
inverse_dir = BoundaryOffsetInfo.inv_dir(direction_symbol)
return [Assignment(pdf_field[neighbor](inverse_dir), pdf_field(inverse_dir)),
......@@ -223,6 +243,7 @@ class NeumannByCopy(Boundary):
class StreamInConstant(Boundary):
def __init__(self, constant, name=None):
raise NotImplementedError() # not yet operable
super(StreamInConstant, self).__init__(name)
self._constant = constant
......
lbmpy/boundaries/boundaryhandling.py
View file @ dd1cbd09
import numpy as np
import sympy as sp
from pystencils import Assignment, TypedSymbol, create_indexed_kernel
from pystencils.backends.cbackend import CustomCodeNode
from pystencils.boundaries import BoundaryHandling
from pystencils.boundaries.boundaryhandling import BoundaryOffsetInfo
from lbmpy.advanced_streaming.indexing import BetweenTimestepsIndexing
from lbmpy.advanced_streaming.utility import is_inplace, Timestep, AccessPdfValues
from pystencils import Field, Assignment, TypedSymbol, create_indexed_kernel
from pystencils.stencil import inverse_direction
from pystencils.boundaries import BoundaryHandling
from pystencils.boundaries.createindexlist import numpy_data_type_for_boundary_object
from pystencils.backends.cbackend import CustomCodeNode
class LatticeBoltzmannBoundaryHandling(BoundaryHandling):
def __init__(self, lb_method, data_handling, pdf_field_name, name="boundary_handling", flag_interface=None,
target='cpu', openmp=True):
self.lb_method = lb_method
"""
Enables boundary handling for LBM simulations with advanced streaming patterns.
For the in-place patterns AA and EsoTwist, two kernels are generated for a boundary
object and the right one selected depending on the time step.
"""