Enable pickling of ExpData

CHANGELOG.md

@@ -65,6 +65,7 @@ See also our [versioning policy](https://amici.readthedocs.io/en/latest/versioni
   multi-processing contexts. This works only if the amici-generated model
   package exists in the same file system location and does not change until
   unpickling.
+* `amici.ExpData` is now picklable.
 
 ## v0.X Series
 

python/sdist/amici/swig_wrappers.py

@@ -397,3 +397,26 @@ def file_checksum(
         for chunk in iter(lambda: f.read(chunk_size), b""):
             h.update(chunk)
     return h.hexdigest()
+
+
+def restore_edata(
+    init_args: Sequence,
+    simulation_parameter_dict: dict[str, Any],
+) -> amici_swig.ExpData:
+    """
+    Recreate an ExpData instance.
+
+    For use in ExpData.__reduce__.
+    """
+    edata = amici_swig.ExpData(*init_args)
+
+    edata.pscale = amici.parameter_scaling_from_int_vector(
+        simulation_parameter_dict.pop("pscale")
+    )
+    for key, value in simulation_parameter_dict.items():
+        if key == "timepoints":
+            # timepoints are set during ExpData construction
+            continue
+        assert hasattr(edata, key)
+        setattr(edata, key, value)
+    return edata

python/tests/test_swig_interface.py

@@ -697,3 +697,18 @@ def test_pickle_model(sbml_example_presimulation_module):
         model.get_steady_state_sensitivity_mode()
         != model_pickled.get_steady_state_sensitivity_mode()
     )
+
+
+def test_pickle_edata():
+    ny = 2
+    nz = 3
+    ne = 4
+    nt = 5
+    edata = amici.ExpData(ny, nz, ne, range(nt))
+    edata.set_observed_data(list(np.arange(ny * nt, dtype=float)))
+    edata.pscale = amici.parameter_scaling_from_int_vector(
+        [amici.ParameterScaling.log10] * 5
+    )
+
+    edata_pickled = pickle.loads(pickle.dumps(edata))
+    assert edata == edata_pickled

swig/amici.i

@@ -155,6 +155,23 @@ wrap_unique_ptr(ExpDataPtr, amici::ExpData)
 %naturalvar amici::SimulationParameters::reinitialization_state_idxs_sim;
 %naturalvar amici::SimulationParameters::reinitialization_state_idxs_presim;
 
+%extend amici::SimulationParameters {
+%pythoncode %{
+    def __iter__(self):
+        for attr_name in dir(self):
+            if (
+                not attr_name.startswith('_')
+                and attr_name not in ("this", "thisown")
+                and not callable(attr_val := getattr(self, attr_name))
+            ):
+                if isinstance(attr_val, (DoubleVector, ParameterScalingVector)):
+                    yield attr_name, tuple(attr_val)
+                else:
+                    yield attr_name, attr_val
+%}
+}
+
+
 // DO NOT IGNORE amici::SimulationParameters, amici::ModelDimensions, amici::CpuTimer
 %ignore amici::ModelContext;
 %ignore amici::ContextManager;

swig/edata.i

@@ -102,6 +102,27 @@ def __deepcopy__(self, memo):
     # invoke copy constructor
     return type(self)(self)
 
+def __reduce__(self):
+    from amici.swig_wrappers import restore_edata
+
+    return (
+        restore_edata,
+        (
+            # ExpData ctor arguments
+            (
+                self.nytrue(),
+                self.nztrue(),
+                self.nmaxevent(),
+                self.get_timepoints(),
+                self.get_observed_data(),
+                self.get_observed_data_std_dev(),
+                self.get_observed_events(),
+                self.get_observed_events_std_dev(),
+            ),
+            dict(self)
+        ),
+        {}
+    )
 %}
 };
 %extend std::unique_ptr<amici::ExpData> {