Merge pull request #2758 from devitocodes/tkn-type

api: fix subdimension thickness type

Author: mloubout

devito/types/dimension.py

@@ -613,7 +613,7 @@ class AbstractSubDimension(DerivedDimension):
     __rargs__ = DerivedDimension.__rargs__ + ('thickness',)
     __rkwargs__ = ()
 
-    _thickness_type = Symbol
+    _thickness_type = Thickness
 
     def __init_finalize__(self, name, parent, thickness, **kwargs):
         super().__init_finalize__(name, parent)
@@ -634,7 +634,7 @@ def _symbolic_thickness(self, **kwargs):
         kwargs = {'dtype': np.int32, 'is_const': True, 'nonnegative': True}
 
         names = ["%s_%stkn" % (self.parent.name, s) for s in ('l', 'r')]
-        return SubDimensionThickness(*[Symbol(name=n, **kwargs) for n in names])
+        return SubDimensionThickness(*[Thickness(name=n, **kwargs) for n in names])
 
     @cached_property
     def symbolic_min(self):