remove getstate and setstate from Stack, and base argument from init

refl1d/model.py

@@ -276,20 +276,21 @@ class Stack(Layer):
     thickness: Parameter = field(metadata={"description": "always equals the sum of the layer thicknesses"})
 
     def __init__(
-        self, base=None, layers=None, name="Stack", interface=None, thickness: Optional[Union[Parameter, float]] = None
+        self,
+        layers: Optional[Union["Stack", List[Union["Slab", "Repeat"]]]] = None,
+        name: str = "Stack",
+        interface=None,
+        thickness: Optional[Union[Parameter, float]] = None,
     ):
         self.name = name
         self.interface = None
         self._layers = []
         # make sure thickness.id is persistent through serialization:
-        thickness_id = getattr(thickness, "id", None)
         thickness = thickness if thickness is not None else 0
-        self.thickness = Parameter.default(thickness, name=name + " thickness", id=thickness_id)
+        self.thickness = Parameter.default(thickness, name=name + " thickness")
         self._set_thickness()
-        if layers is not None and base is None:
-            base = layers
-        if base is not None:
-            self.add(base)
+        if layers is not None:
+            self.add(layers)
 
     @property
     def layers(self):
@@ -330,15 +331,6 @@ def add(self, other):
                 L = [other]
             self._layers.extend(_check_layer(el) for el in L)
 
-    def __getstate__(self):
-        return self.interface, self._layers, self.name, self.thickness
-
-    def __setstate__(self, state):
-        self.interface, self._layers, self.name, self.thickness = state
-        # TODO: not clear that this is needed here.  The thickness parameter
-        # from __getstate__ should have a valid expression in it.
-        self._set_thickness()
-
     def __copy__(self):
         stack = Stack()
         stack.interface = self.interface

tests/refl1d/stack_test.py

@@ -0,0 +1,36 @@
+from refl1d.names import Slab, Stack, SLD
+from copy import deepcopy
+from bumps.serialize import serialize, deserialize
+import pickle
+import dill
+
+
+def test_stack_serialization():
+    """test that stack can be serialized and deserialized with all the methods we use,
+    preserving the functioning of the Calculation object for the total thickness"""
+    sample = Slab(SLD(rho=10), thickness=10) | Slab(SLD(rho=10), thickness=20) | Slab(SLD(rho=10), thickness=30)
+    thickness_plus = sample.thickness + 100  # expression
+
+    ser_t, ser_s = deserialize(serialize([thickness_plus, sample]))
+    assert ser_t.value == 160
+    ser_s[0].thickness.value += 40
+    assert ser_t.value == 200
+
+    dc_t, dc_s = deepcopy([thickness_plus, sample])
+    assert dc_t.value == 160
+    dc_s[0].thickness.value += 40
+    assert dc_t.value == 200
+
+    pickle_t, pickle_s = pickle.loads(pickle.dumps([thickness_plus, sample]))
+    assert pickle_t.value == 160
+    pickle_s[0].thickness.value += 40
+    assert pickle_t.value == 200
+
+    dill_t, dill_s = dill.loads(dill.dumps([thickness_plus, sample]))
+    assert dill_t.value == 160
+    dill_s[0].thickness.value += 40
+    assert dill_t.value == 200
+
+    assert thickness_plus.value == 160
+    sample[0].thickness.value += 40
+    assert thickness_plus.value == 200