use indirect access only for jacobians

python/dune/codegen/blockstructured/accumulation.py

 from dune.codegen.blockstructured.tools import sub_element_inames, name_accumulation_alias
-from dune.codegen.generation import accumulation_mixin, instruction
+from dune.codegen.generation import accumulation_mixin, instruction, get_global_context_value
 from dune.codegen.loopy.target import dtype_floatingpoint
 from dune.codegen.options import get_form_option
 from dune.codegen.pdelab.geometry import world_dimension, name_intersection_geometry_wrapper
@@ -16,10 +16,10 @@ from loopy.match import Writes
 @accumulation_mixin("blockstructured")
 class BlockStructuredAccumulationMixin(GenericAccumulationMixin):
     def generate_accumulation_instruction(self, expr):
-        if get_form_option('vectorization_blockstructured'):
-            return generate_accumulation_instruction_vectorized(expr, self)
-        else:
+        if get_global_context_value("form_type") == "jacobians":
             return generate_accumulation_instruction(expr, self)
+        else:
+            return generate_accumulation_instruction_vectorized(expr, self)
 
 
 @function_mangler