Creationfunctions now update LBMConfig. Small fix to `GenericDiscreteEquilibrium`.

lbmpy/creationfunctions.py

@@ -39,6 +39,9 @@ of the generated code is specified.
         This step compiles the AST into an executable function, either for CPU or GPUs. This function
         behaves like a normal Python function and runs one LBM time step.
 
+Each stage (apart from *Function*) also adds its result to the given `LBMConfig` object. The `LBMConfig`
+thus coalesces all information defining the LBM kernel.
+
 The function :func:`create_lb_function` runs the whole pipeline, the other functions in this module
 execute this pipeline only up to a certain step. Each function optionally also takes the result of the previous step.
 
@@ -525,11 +528,12 @@ def create_lb_ast(update_rule=None, lbm_config=None, lbm_optimisation=None, conf
     field_types = set(fa.field.dtype for fa in update_rule.defined_symbols if isinstance(fa, Field.Access))
 
     config = replace(config, data_type=collate_types(field_types), ghost_layers=1)
-    res = create_kernel(update_rule, config=config)
+    ast = create_kernel(update_rule, config=config)
 
-    res.method = update_rule.method
-    res.update_rule = update_rule
-    return res
+    ast.method = update_rule.method
+    ast.update_rule = update_rule
+    lbm_config.ast = ast
+    return ast
 
 
 @disk_cache_no_fallback
@@ -568,8 +572,9 @@ def create_lb_update_rule(collision_rule=None, lbm_config=None, lbm_optimisation
         dst_field = src_field.new_field_with_different_name(lbm_config.temporary_field_name)
 
     kernel_type = lbm_config.kernel_type
+    update_rule = None
     if kernel_type == 'stream_pull_only':
-        return create_stream_pull_with_output_kernel(lb_method, src_field, dst_field, lbm_config.output)
+        update_rule = create_stream_pull_with_output_kernel(lb_method, src_field, dst_field, lbm_config.output)
     else:
         if kernel_type == 'default_stream_collide':
             if lbm_config.streaming_pattern == 'pull' and any(lbm_optimisation.builtin_periodicity):
@@ -582,7 +587,10 @@ def create_lb_update_rule(collision_rule=None, lbm_config=None, lbm_optimisation
             accessor = kernel_type
         else:
             raise ValueError("Invalid value of parameter 'kernel_type'", lbm_config.kernel_type)
-        return create_lbm_kernel(collision_rule, src_field, dst_field, accessor)
+        update_rule = create_lbm_kernel(collision_rule, src_field, dst_field, accessor)
+
+    lbm_config.update_rule = update_rule
+    return update_rule
 
 
 @disk_cache_no_fallback
@@ -680,6 +688,7 @@ def create_lb_collision_rule(lb_method=None, lbm_config=None, lbm_optimisation=N
     if lbm_optimisation.cse_global:
         collision_rule = sympy_cse(collision_rule)
 
+    lbm_config.collision_rule = collision_rule
     return collision_rule
 
 
@@ -756,6 +765,7 @@ def create_lb_method(lbm_config=None, **params):
     if lbm_config.entropic:
         method.set_conserved_moments_relaxation_rate(relaxation_rates[0])
 
+    lbm_config.method = method
     return method
 
 

lbmpy/equilibrium/generic_discrete_equilibrium.py

@@ -47,6 +47,10 @@ class GenericDiscreteEquilibrium(AbstractEquilibrium):
                  deviation_only=False):
         super().__init__(dim=stencil.D)
 
+        if len(equilibrium_pdfs) != stencil.Q:
+            raise ValueError(f"Wrong number of PDFs."
+                             f"On the {stencil} stencil, exactly {stencil.Q} populations must be passed!")
+
         self._stencil = stencil
         self._pdfs = tuple(equilibrium_pdfs)
         self._zeroth_order_moment_symbol = zeroth_order_moment_symbol