Adjust vectorization for systems

python/dune/perftool/sumfact/symbolic.py

@@ -168,7 +168,7 @@ class SumfactKernel(SumfactKernelBase, ImmutableRecord, prim.Variable):
         work on the same input coefficient (and are suitable for simultaneous
         treatment because of that)
         """
-        return (self.input, self.restriction, self.accumvar)
+        return (self.input, self.restriction, self.accumvar, self.trial_element_index)
 
     #
     # Some convenience methods to extract information about the sum factorization kernel