diff --git a/python/dune/perftool/pdelab/localoperator.py b/python/dune/perftool/pdelab/localoperator.py
index 3dc64c1a9802ef23d431f63e14e8dd4362de8543..e11f3e636e7e3951622a987f886fbb0417dc0078 100644
--- a/python/dune/perftool/pdelab/localoperator.py
+++ b/python/dune/perftool/pdelab/localoperator.py
@@ -7,13 +7,19 @@ from dune.perftool.cgen.clazz import BaseClass, ClassMember
 from pytools import memoize
 
 
+@symbol
+def name_initree_constructor_param():
+    return "iniParams"
+
+
 @class_member("operator")
 def define_initree(name):
+    param_name = name_initree_constructor_param()
     include_file('dune/common/parametertree.hh', filetag="operatorfile")
-    constructor_parameter("const Dune::ParameterTree&", "iniParams", classtag="operator", constructortag="iniconstructor")
-    initializer_list("_iniParams", ["iniParams"], classtag="operator")
+    constructor_parameter("const Dune::ParameterTree&", param_name, classtag="operator", constructortag="iniconstructor")
+    initializer_list(name, [param_name], classtag="operator")
 
-    return ("const Dune::ParameterTree&", "_iniParams")
+    return ("const Dune::ParameterTree&", name)
 
 
 @symbol
@@ -42,8 +48,9 @@ def measure_specific_details(measure):
 
             # Add the initializer list for that base class
             ini = name_initree_member()
+            ini_constructor = name_initree_constructor_param()
             initializer_list("Dune::PDELab::NumericalJacobian{}<{}>".format(which, loptype),
-                             ["{}.get(\"numerical_epsilon.{}\", 1e-9)".format(ini, which.lower())],
+                             ["{}.get<double>(\"numerical_epsilon.{}\", 1e-9)".format(ini_constructor, ini, which.lower())],
                              classtag="operator")
 
     if measure == "cell":