compiler: Polish code

devito/symbolics/manipulation.py

@@ -287,7 +287,7 @@ def pow_to_mul(expr):
             # E.g., a Symbol, or possibly a generic expression
             return expr
         if exp > 10 or exp < -10 or exp == 0:
-            # Large and non-integer powers remain untouched
+            # Large powers remain untouched
             return expr
         elif exp == -1 or int(exp) != exp:
             # Reciprocals and fractional powers also remain untouched,

devito/types/basic.py

@@ -1017,10 +1017,9 @@ def __padding_setup_smart__(self, **kwargs):
             return nopadding
 
         # The padded Dimension
-        candidates = self.space_dimensions
-        if not candidates:
+        if not self.space_dimensions:
             return nopadding
-        d = candidates[-1]
+        d = self.space_dimensions[-1]
 
         mmts = configuration['platform'].max_mem_trans_size(self.__padding_dtype__)
         remainder = self._size_nopad[d] % mmts

tests/test_dimension.py

@@ -211,6 +211,10 @@ def test_modulo_dims_generation_v2(self):
         assert np.all(f.data[4] == 4)
 
     def test_degenerate_to_zero(self):
+        """
+        Check that if `save=Buffer(1)` is used, then the TimeFunction doesn't
+        need any ModuloDimension for indexing.
+        """
         grid = Grid(shape=(10, 10))
 
         u = TimeFunction(name='u', grid=grid, save=Buffer(1))