compiler: Simplify SubFunction

devito/types/dense.py

@@ -20,7 +20,7 @@
 from devito.finite_differences import Differentiable, generate_fd_shortcuts
 from devito.tools import (ReducerMap, as_tuple, c_restrict_void_p, flatten, is_integer,
                           memoized_meth, dtype_to_ctype, humanbytes)
-from devito.types.dimension import Dimension
+from devito.types.dimension import Dimension, DynamicDimension
 from devito.types.args import ArgProvider
 from devito.types.caching import CacheManager
 from devito.types.basic import AbstractFunction, Size
@@ -1449,16 +1449,10 @@ class SubFunction(Function):
     """
     A Function bound to a "parent" DiscreteFunction.
 
-    A SubFunction hands control of argument binding and halo exchange to its
-    parent DiscreteFunction.
+    A SubFunction hands control of argument binding and halo exchange to the
+    DiscreteFunction it's bound to.
     """
 
-    __rkwargs__ = Function.__rkwargs__ + ('parent',)
-
-    def __init_finalize__(self, *args, **kwargs):
-        super(SubFunction, self).__init_finalize__(*args, **kwargs)
-        self._parent = kwargs['parent']
-
     def __padding_setup__(self, **kwargs):
         # SubFunctions aren't expected to be used in time-consuming loops
         return tuple((0, 0) for i in range(self.ndim))
@@ -1470,12 +1464,8 @@ def _arg_values(self, **kwargs):
         if self.name in kwargs:
             raise RuntimeError("`%s` is a SubFunction, so it can't be assigned "
                                "a value dynamically" % self.name)
-        else:
-            return self._parent._arg_defaults(alias=self._parent).reduce_all()
 
-    @property
-    def parent(self):
-        return self._parent
+        return self._arg_defaults(alias=self)
 
     @property
     def origin(self):

devito/types/sparse.py

@@ -1179,6 +1179,15 @@ class PrecomputedSparseTimeFunction(AbstractSparseTimeFunction,
                                        PrecomputedSparseFunction.__rkwargs__))
 
 
+# *** MatrixSparse*Function API
+# This is mostly legacy stuff which often escapes the devito's modus operandi
+
+class DynamicSubFunction(SubFunction):
+
+    def _arg_defaults(self, **kwargs):
+        return {}
+
+
 class MatrixSparseTimeFunction(AbstractSparseTimeFunction):
     """
     A specialised type of SparseTimeFunction where the interpolation is externally
@@ -1378,7 +1387,7 @@ def __init_finalize__(self, *args, **kwargs):
         else:
             nnz_size = 1
 
-        self._mrow = SubFunction(
+        self._mrow = DynamicSubFunction(
             name='mrow_%s' % self.name,
             dtype=np.int32,
             dimensions=(self.nnzdim,),
@@ -1387,7 +1396,7 @@ def __init_finalize__(self, *args, **kwargs):
             parent=self,
             allocator=self._allocator,
         )
-        self._mcol = SubFunction(
+        self._mcol = DynamicSubFunction(
             name='mcol_%s' % self.name,
             dtype=np.int32,
             dimensions=(self.nnzdim,),
@@ -1396,7 +1405,7 @@ def __init_finalize__(self, *args, **kwargs):
             parent=self,
             allocator=self._allocator,
         )
-        self._mval = SubFunction(
+        self._mval = DynamicSubFunction(
             name='mval_%s' % self.name,
             dtype=self.dtype,
             dimensions=(self.nnzdim,),
@@ -1413,8 +1422,8 @@ def __init_finalize__(self, *args, **kwargs):
         self.par_dim_to_nnz_dim = DynamicDimension('par_dim_to_nnz_%s' % self.name)
 
         # This map acts as an indirect sort of the sources according to their
-        # position along the parallelisation Dimension
-        self._par_dim_to_nnz_map = SubFunction(
+        # position along the parallelisation dimension
+        self._par_dim_to_nnz_map = DynamicSubFunction(
             name='par_dim_to_nnz_map_%s' % self.name,
             dtype=np.int32,
             dimensions=(self.par_dim_to_nnz_dim,),
@@ -1423,7 +1432,7 @@ def __init_finalize__(self, *args, **kwargs):
             space_order=0,
             parent=self,
         )
-        self._par_dim_to_nnz_m = SubFunction(
+        self._par_dim_to_nnz_m = DynamicSubFunction(
             name='par_dim_to_nnz_m_%s' % self.name,
             dtype=np.int32,
             dimensions=(self._par_dim,),
@@ -1432,7 +1441,7 @@ def __init_finalize__(self, *args, **kwargs):
             space_order=0,
             parent=self,
         )
-        self._par_dim_to_nnz_M = SubFunction(
+        self._par_dim_to_nnz_M = DynamicSubFunction(
             name='par_dim_to_nnz_M_%s' % self.name,
             dtype=np.int32,
             dimensions=(self._par_dim,),

tests/test_interpolation.py

@@ -689,7 +689,6 @@ def test_msf_interpolate():
 
     eqn_inject = sf.inject(field=u, expr=sf)
     op2 = Operator(eqn_inject)
-
     op2(time_m=0, time_M=4)
 
     # There should be 4 points touched for each source point