review comments

Author: pbrubeck

firedrake/slate/slate.py

@@ -336,54 +336,48 @@ def __add__(self, other):
             other = as_slate(other)
             return Add(self, other)
         except TypeError:
-            raise NotImplementedError("Type(s) for + not supported: '%s' '%s'"
-                                      % (type(self), type(other)))
+            return NotImplemented
 
     def __radd__(self, other):
         # If other cannot be converted into a TensorBase, raise NotImplementedError.
         # Otherwise, delegate action to other.
         try:
             other = as_slate(other)
-            return other.__add__(self)
+            return other + self
         except TypeError:
-            raise NotImplementedError("Type(s) for + not supported: '%s' '%s'"
-                                      % (type(other), type(self)))
+            return NotImplemented
 
     def __sub__(self, other):
         try:
             other = as_slate(other)
             return Add(self, Negative(other))
         except TypeError:
-            raise NotImplementedError("Type(s) for - not supported: '%s' '%s'"
-                                      % (type(self), type(other)))
+            return NotImplemented
 
     def __rsub__(self, other):
         # If other cannot be converted into a TensorBase, raise NotImplementedError.
         # Otherwise, delegate action to other.
         try:
             other = as_slate(other)
-            return other.__sub__(self)
+            return other - self
         except TypeError:
-            raise NotImplementedError("Type(s) for - not supported: '%s' '%s'"
-                                      % (type(other), type(self)))
+            return NotImplemented
 
     def __mul__(self, other):
         try:
             other = as_slate(other)
             return Mul(self, other)
         except TypeError:
-            raise NotImplementedError("Type(s) for * not supported: '%s' '%s'"
-                                      % (type(self), type(other)))
+            return NotImplemented
 
     def __rmul__(self, other):
         # If other cannot be converted into a TensorBase, raise NotImplementedError.
         # Otherwise, delegate action to other.
         try:
             other = as_slate(other)
-            return other.__mul__(self)
+            return other * self
         except TypeError:
-            raise NotImplementedError("Type(s) for * not supported: '%s' '%s'"
-                                      % (type(other), type(self)))
+            return NotImplemented
 
     def __neg__(self):
         return Negative(self)

firedrake/variational_solver.py

@@ -136,6 +136,8 @@ def compute_bc_lifting(J, u):
         """Return the action of the bilinear form J (without bcs) on a Function u."""
         if isinstance(J, MatrixBase) and J.has_bcs:
             # Extract the full form without bcs
+            if not isinstance(J.a, (ufl.BaseForm, slate.slate.TensorBase)):
+                raise TypeError(f"Could not remove bcs from {type(J).__name__}.")
             J = J.a
         return ufl_expr.action(J, u)