diff --git a/Readme.md b/Readme.md
index af9e8765bd2fc61e629bebcc4658e3f0743645e0..35a4f470363f3463f9600b28f85ce3bf5a6d001c 100644
--- a/Readme.md
+++ b/Readme.md
@@ -11,6 +11,7 @@ Install
 
 To install PySWIFT, you can run the following command: `python3 setup.py install --with-swift SWIFT_PATH --user`.
 The setup script will read all your parameters in the config file of swift, therefore you need to reinstall PySWIFT with each configuration of SWIFT.
+You may need to remove the build directory to recompile PySWIFT.
 
 
 Adding a new structure
diff --git a/pyswiftsim/structure.py b/pyswiftsim/structure.py
index 45f76f684c45eb1c28fba1e97cd78db4d1c02050..353b8f51210d0ec1d76a5ba40c3f2ae004363f61 100644
--- a/pyswiftsim/structure.py
+++ b/pyswiftsim/structure.py
@@ -347,14 +347,16 @@ class Part(SwiftStruct):
 #                                                                    #
 ######################################################################
 class Parameter(SwiftStruct):
-    _format = "{line_size}c{line_size}c".format(
+    _format = "{line_size}c{line_size}cii".format(
             line_size=PARSER_MAX_LINE_SIZE
         )
 
     _name = [
-            "name",
-            "value"
-        ]
+        "name",
+        "value",
+        "used",
+        "is_default"
+    ]
 
     def __init__(self, data, parent=None):
         super().__init__(self.struct_format, data, parent)
diff --git a/test/test_struct.py b/test/test_struct.py
index 6d42775c0ebe8814dc5ee05561ccc6762b40e3c8..2d9df52e88b5a247619ce1df6065bf7c72b6076f 100644
--- a/test/test_struct.py
+++ b/test/test_struct.py
@@ -18,46 +18,12 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
 
 from pyswiftsim import wrapper
-from pyswiftsim import structure
 
-us = wrapper.unitSystemTestStruct()
+filename = "parameter_example.yml"
+params = wrapper.parserReadFile(filename)
 
-print(us)
-
-part = wrapper.partTestStruct()
-
-print(part)
-
-#us = structure.Units(t)
+print(params)
 
-#print(type(us), us.struct_name)
-#print(us.struct_size_format)
-
-#for i in us.struct_name:
-#    print(i, getattr(us, i))
-
-"""
-print(us.pos)
-us.pos = [12., 16., 11.]
-#us.pos[0] = 10.
+us = wrapper.unitSystemInit(params)
 
 print(us)
-print(us.pos)
-
-print("setitem")
-us.pos[2] = 20.
-
-print(us.pos)
-print(us)
-
-d = {}
-d["UnitMass_in_cgs"] = 1.
-d["UnitLength_in_cgs"] = 2.
-d["UnitTime_in_cgs"] = 3.
-d["UnitCurrent_in_cgs"] = 4.
-d["UnitTemperature_in_cgs"] = 5.
-
-us = structure.UnitSystem(d)
-
-print(us)
-"""