Deprecation of old boundary API

lbmpy/boundaries/boundaryconditions.py

@@ -7,8 +7,8 @@ from lbmpy.simplificationfactory import create_simplification_strategy
 from lbmpy.advanced_streaming.indexing import NeighbourOffsetArrays
 
 
-class Boundary:
-    """Base class for all boundary classes that use the AdvancedStreamingBoundaryIndexing"""
+class LbBoundary:
+    """Base class that all boundaries should derive from"""
 
     inner_or_boundary = True
     single_link = False
@@ -69,7 +69,7 @@ class Boundary:
 # end class Boundary
 
 
-class NoSlip(Boundary):
+class NoSlip(LbBoundary):
 
     def __init__(self, name=None):
         """Set an optional name here, to mark boundaries, for example for force evaluations"""
@@ -94,7 +94,7 @@ class NoSlip(Boundary):
 # end class NoSlip
 
 
-class UBB(Boundary):
+class UBB(LbBoundary):
     """Velocity bounce back boundary condition, enforcing specified velocity at obstacle"""
 
     def __init__(self, velocity, adapt_velocity_to_force=False, dim=None, name=None):
@@ -135,7 +135,7 @@ class UBB(Boundary):
         direction = dir_symbol
 
         assert self.dim == lb_method.dim, \
-               f"Dimension of UBB ({self.dim}) does not match dimension of method ({lb_method.dim})"
+            f"Dimension of UBB ({self.dim}) does not match dimension of method ({lb_method.dim})"
 
         neighbor_offset = NeighbourOffsetArrays.neighbour_offset(direction, lb_method.stencil)
 
@@ -174,7 +174,7 @@ class UBB(Boundary):
 # end class UBB
 
 
-class FixedDensity(Boundary):
+class FixedDensity(LbBoundary):
 
     def __init__(self, density, name=None):
         if name is None:
@@ -221,7 +221,7 @@ class FixedDensity(Boundary):
 # end class FixedDensity
 
 
-class NeumannByCopy(Boundary):
+class NeumannByCopy(LbBoundary):
 
     def get_additional_code_nodes(self, lb_method):
         return [NeighbourOffsetArrays(lb_method.stencil)]
@@ -240,7 +240,7 @@ class NeumannByCopy(Boundary):
 # end class NeumannByCopy
 
 
-class StreamInConstant(Boundary):
+class StreamInConstant(LbBoundary):
     def __init__(self, constant, name=None):
         super(StreamInConstant, self).__init__(name)
         self._constant = constant
@@ -260,3 +260,60 @@ class StreamInConstant(Boundary):
     def __eq__(self, other):
         return type(other) == StreamInConstant
 # end class StreamInConstant
+
+
+#   ------------------------- Old, Deprecated Implementation -------------------------
+
+class Boundary:
+
+    inner_or_boundary = True
+    single_link = False
+
+    def __init__(self, name=None):
+        from lbmpy.boundaries.boundaryhandling import deprecation_message
+        deprecation_message()
+        self._name = name
+
+    def __call__(self, pdf_field, direction_symbol, 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
+        """
+        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
+
+    @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

lbmpy/boundaries/boundaryhandling.py

@@ -62,7 +62,7 @@ class LatticeBoltzmannBoundaryHandling(BoundaryHandling):
         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(
+        return create_lattice_boltzmann_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)
@@ -173,9 +173,14 @@ class LbmWeightInfo(CustomCodeNode):
 # end class LbmWeightInfo
 
 
-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, **kernel_creation_args):
+def create_lattice_boltzmann_boundary_kernel(pdf_field, index_field, lb_method, boundary_functor,
+                                             prev_timestep=Timestep.BOTH, streaming_pattern='pull',
+                                             target='cpu', openmp=True, **kernel_creation_args):
+    from lbmpy.boundaries.boundaryconditions import Boundary as OldBoundary
+    if isinstance(boundary_functor, OldBoundary):
+        return create_lattice_boltzmann_boundary_kernel_old(pdf_field, index_field, lb_method, boundary_functor,
+                                                            target=target, openmp=openmp, **kernel_creation_args)
+
     index_dtype = index_field.dtype.numpy_dtype.fields['dir'][0]
     offsets_dtype = index_field.dtype.numpy_dtype.fields['x'][0]
     indexing = BetweenTimestepsIndexing(
@@ -200,3 +205,28 @@ def create_advanced_streaming_boundary_kernel(pdf_field, index_field, lb_method,
         kernel.body.insert_front(node)
     kernel.body.insert_front(index_arrs_node)
     return kernel
+
+
+#   ----------------------------- Old, Deprecated Implementation -----------------------
+
+def deprecation_message():
+    import warnings
+    deprecation_message = "The old code generation scheme for LB boundaries has been deprecated. " \
+                          + "Please update your boundary implementation to derive from ``LbBoundary`` " \
+                          + "and use the new implementation scheme based on `BetweenTimestepsIndexing`."
+    warnings.simplefilter('always', DeprecationWarning)
+    warnings.warn(deprecation_message, DeprecationWarning, stacklevel=2)
+    warnings.simplefilter('default', DeprecationWarning)
+
+
+def create_lattice_boltzmann_boundary_kernel_old(pdf_field, index_field, lb_method, boundary_functor,
+                                                 target='cpu', openmp=True, **kernel_creation_args):
+    deprecation_message()
+    from pystencils.boundaries.boundaryhandling import BoundaryOffsetInfo
+    elements = [BoundaryOffsetInfo(lb_method.stencil), LbmWeightInfo(lb_method)]
+    index_arr_dtype = index_field.dtype.numpy_dtype
+    dir_symbol = TypedSymbol("dir", index_arr_dtype.fields['dir'][0])
+    elements += [Assignment(dir_symbol, index_field[0]('dir'))]
+    elements += boundary_functor(pdf_field=pdf_field, direction_symbol=dir_symbol,
+                                 lb_method=lb_method, index_field=index_field)
+    return create_indexed_kernel(elements, [index_field], target=target, cpu_openmp=openmp, **kernel_creation_args)

lbmpy_tests/advanced_streaming/test_advanced_streaming_noslip.py

@@ -3,7 +3,7 @@ import sympy as sp
 
 from lbmpy.advanced_streaming import Timestep
 from lbmpy.boundaries import NoSlip
-from lbmpy.boundaries.boundaryhandling import create_advanced_streaming_boundary_kernel
+from lbmpy.boundaries.boundaryhandling import create_lattice_boltzmann_boundary_kernel
 from lbmpy.advanced_streaming.utility import even_accessors, odd_accessors, streaming_patterns, inverse_dir_index, AccessPdfValues
 from lbmpy.creationfunctions import create_lb_method
 from lbmpy.stencils import get_stencil
@@ -48,12 +48,12 @@ def test_advanced_streaming_noslip_single_cell(stencil, streaming_pattern, prev_
                     shape=(TypedSymbol("indexVectorSize", create_type(np.int64)), 1), strides=(1, 1))
     index_vector = np.array([ pos + (d,) for d in range(q) ], dtype=index_struct_dtype)
 
-    flex_ast = create_advanced_streaming_boundary_kernel(pdf_field, 
+    ast = create_lattice_boltzmann_boundary_kernel(pdf_field, 
                     index_field, lb_method, noslip,
                     prev_timestep=prev_timestep,
                     streaming_pattern=streaming_pattern)
 
-    flex_kernel = flex_ast.compile()
+    flex_kernel = ast.compile()
     
     flex_kernel(pdfs=pdfs, indexVector=index_vector, indexVectorSize=len(index_vector))