Remove the validity code

It was nonsense, as it did everything done lateron anyway.

python/dune/perftool/compile.py

@@ -33,11 +33,7 @@ def read_ufl(uflfile):
     # We do not expect more than one form
     assert len(data.forms) == 1
 
-    # TODO As validity is implemented right now, this is nonsense.
-    # Might as well formulate it as a try statement!
-#     from dune.perftool.ufl.validity import check_validity
-#     if not check_validity(form):
-        # apply some transformations unconditionally!
+    # apply some transformations unconditionally!
     from dune.perftool.ufl.transformations import transform_form
     from dune.perftool.ufl.transformations.splitarguments import split_arguments
     from dune.perftool.ufl.transformations.indexpushdown import pushdown_indexed

python/dune/perftool/ufl/validity.py

-from __future__ import absolute_import
-from ufl.algorithms import MultiFunction
-
-
-def check_validity(uflexpr):
-    """ check an UFL expression (usually an integrand) for
-    compatibility with the dune-pdelab code generation tool chain.
-
-    The assumptions made are the following:
-    - The expression is the sum of subtrees, where the number of test
-      function terms in such subtree is equal the rank of the entire expression.
-    """
-    from ufl import Form
-    from ufl.classes import Expr
-
-    def check(term):
-        try:
-            from dune.perftool.ufl.transformations.extract_accumulation_terms import split_into_accumulation_terms
-            split_into_accumulation_terms(term)
-            return True
-        except AssertionError:
-            from dune.perftool.ufl.transformations import print_expression
-            print_expression(term)
-            return False
-
-    if isinstance(uflexpr, Form):
-        for integral in uflexpr.integrals():
-            if not check(integral.integrand()):
-                return False
-        return True
-
-    if isinstance(uflexpr, Expr):
-        return check(uflexpr)
-
-    raise TypeError("Unknown object type in check_validity: {}".format(type(uflexpr)))