diff --git a/src/scgenerator/parameter.py b/src/scgenerator/parameter.py
index e500b7a..d727eff 100644
--- a/src/scgenerator/parameter.py
+++ b/src/scgenerator/parameter.py
@@ -218,6 +218,7 @@ class Parameter:
         converter: Callable = None,
         default=None,
         display_info: tuple[float, str] = None,
+        can_pickle: bool = True,
     ):
         """
         Single parameter
@@ -241,6 +242,7 @@ class Parameter:
         self.converter = converter
         self.default = default
         self.display_info = display_info
+        self.can_pickle = can_pickle
 
     def __set_name__(self, owner: Type[Parameters], name):
         self.name = name
@@ -407,11 +409,11 @@ class Parameters:
     worker_num: int = Parameter(positive(int))
 
     # computed
-    linear_operator: SpecOperator = Parameter(is_function)
-    nonlinear_operator: SpecOperator = Parameter(is_function)
-    conserved_quantity: Qualifier = Parameter(is_function)
-    fft: Callable[[np.ndarray], np.ndarray] = Parameter(is_function)
-    ifft: Callable[[np.ndarray], np.ndarray] = Parameter(is_function)
+    linear_operator: SpecOperator = Parameter(is_function, can_pickle=False)
+    nonlinear_operator: SpecOperator = Parameter(is_function, can_pickle=False)
+    conserved_quantity: Qualifier = Parameter(is_function, can_pickle=False)
+    fft: Callable[[np.ndarray], np.ndarray] = Parameter(is_function, can_pickle=False)
+    ifft: Callable[[np.ndarray], np.ndarray] = Parameter(is_function, can_pickle=False)
     field_0: np.ndarray = Parameter(type_checker(np.ndarray))
     spec_0: np.ndarray = Parameter(type_checker(np.ndarray))
     beta2: float = Parameter(type_checker(int, float))
@@ -457,12 +459,11 @@ class Parameters:
         yield from (f"{k}={v}" for k, v in self.dump_dict().items())
 
     def __getstate__(self) -> dict[str, Any]:
-        return self.dump_dict(add_metadata=False)
+        return {k: v for k, v in self._param_dico.items() if getattr(self.__class__, k).can_pickle}
 
-    def __setstate__(self, dumped_dict: dict[str, Any]):
-        self._param_dico = dict()
-        for k, v in dumped_dict.items():
-            setattr(self, k, v)
+    def __setstate__(self, param_dico: dict[str, Any]):
+        self._param_dico = param_dico
+        self.frozen = False
 
     def __setattr__(self, k, v):
         if self.frozen and not k.endswith("_file"):
@@ -649,9 +650,12 @@ class Parameters:
             "alpha",
             "gamma_arr",
             "effective_area_arr",
+            "input_time",
+            "input_field",
             "nonlinear_op",
             "linear_op",
             "c_to_a_factor",
+            "hr_w",
         }
         types = (np.ndarray, float, int, str, list, tuple, Path, DataFile)
         c = deepcopy if copy else lambda x: x