Merge pull request #1187 from kornerc/deepcopy

implement `__deepcopy__`

Author: TonyXiang8787

src/power_grid_model/_core/power_grid_model.py

@@ -7,7 +7,7 @@
 """
 
 from enum import IntEnum
-from typing import overload
+from typing import Any, overload
 
 import numpy as np
 
@@ -108,9 +108,18 @@ def copy(self) -> "PowerGridModel":
         new_model._all_component_count = self._all_component_count
         return new_model
 
-    def __copy__(self):
+    def __copy__(self) -> "PowerGridModel":
         return self.copy()
 
+    def __deepcopy__(self, memo: dict[int, Any]) -> "PowerGridModel":
+        # PowerGridModel.copy makes already a deepcopy
+        new_model = self.copy()
+
+        # memorize that this object (self) has been deepcopied
+        memo[id(self)] = new_model
+
+        return new_model
+
     def __new__(cls, *_args, **_kwargs):
         instance = super().__new__(cls)
         instance._model_ptr = ModelPtr()

tests/unit/test_power_grid_model.py

@@ -2,7 +2,7 @@
 #
 # SPDX-License-Identifier: MPL-2.0
 
-from copy import copy
+from copy import copy, deepcopy
 
 import numpy as np
 import pytest
@@ -176,6 +176,37 @@ def test_copy_model(model: PowerGridModel, sym_output):
     compare_result(result, sym_output, rtol=0.0, atol=1e-8)
 
 
+def test_deepcopy_model(model: PowerGridModel, sym_output, update_batch, sym_output_batch):
+    model_other = PowerGridModel({})
+
+    # list containing different models twice
+    model_list = [model, model_other, model, model_other]
+
+    new_model_list = deepcopy(model_list)
+
+    # check if identities are as expected
+    assert id(new_model_list[0]) != id(model_list[0])
+    assert id(new_model_list[1]) != id(model_list[1])
+    assert id(new_model_list[0]) != id(new_model_list[1])
+    assert id(new_model_list[0]) == id(new_model_list[2])
+    assert id(new_model_list[1]) == id(new_model_list[3])
+
+    # check if the deepcopied objects are really independent from the original ones
+    # by modifying the copies and seeing if the original one is impacted by this change
+    new_model_list[0].update(update_data=get_dataset_scenario(update_batch, 0))
+
+    new_expected_result = get_dataset_scenario(sym_output_batch, 0)
+    new_result_0 = new_model_list[0].calculate_power_flow()
+    compare_result(new_result_0, new_expected_result, rtol=0.0, atol=1e-8)
+    # at index 0 and 2 should be the same objects, check if changing the object at index 0
+    # and obtaining a power flow result is ident to the result at index 2
+    new_result_2 = new_model_list[2].calculate_power_flow()
+    compare_result(new_result_2, new_expected_result, rtol=0.0, atol=1e-8)
+
+    result = model.calculate_power_flow()
+    compare_result(result, sym_output, rtol=0.0, atol=1e-8)
+
+
 def test_get_indexer(model: PowerGridModel):
     ids = np.array([2, 2])
     expected_indexer = np.array([0, 0])