solves AttributeError: 'State' object has no attribute 'rng_states' (#2412)

* solves  AttributeError: 'State' object has no attribute 'rng_states'

* update state_dict

* trying test_state_dict in deterministic Engine

* autopep8 fix

* update test_deterministic.py

* Update test_deterministic.py

* autopep8 fix

* update deterministic.py

* update deterministic.py

Co-authored-by: bibhabasumohapatra <[email protected]>

Author: bibhabasumohapatra

ignite/engine/deterministic.py

@@ -179,6 +179,8 @@ class DeterministicEngine(Engine):
     def __init__(self, process_function: Callable[[Engine, Any], Any]):
         super(DeterministicEngine, self).__init__(process_function)
         self.state_dict_user_keys.append("rng_states")
+        if not hasattr(self.state, "rng_states"):
+            setattr(self.state, "rng_states", None)
         self.add_event_handler(Events.STARTED, self._init_run)
         self.add_event_handler(Events.DATALOADER_STOP_ITERATION | Events.TERMINATE_SINGLE_EPOCH, self._setup_seed)
 
@@ -189,9 +191,6 @@ def state_dict(self) -> OrderedDict:
 
     def _init_run(self) -> None:
         self.state.seed = int(torch.randint(0, int(1e9), (1,)).item())
-        if not hasattr(self.state, "rng_states"):
-            setattr(self.state, "rng_states", None)
-
         if torch.cuda.is_available():
             torch.backends.cudnn.deterministic = True
             torch.backends.cudnn.benchmark = False

tests/ignite/engine/test_deterministic.py

@@ -1,6 +1,7 @@
 import os
 import random
 import sys
+from collections.abc import Mapping
 from unittest.mock import patch
 
 import numpy as np
@@ -893,3 +894,13 @@ def test_engine_no_data_asserts():
 
     with pytest.raises(ValueError, match=r"Deterministic engine does not support the option of data=None"):
         trainer.run(max_epochs=10, epoch_length=10)
+
+
+def test_state_dict():
+    engine = DeterministicEngine(lambda e, b: 1)
+    sd = engine.state_dict()
+    assert isinstance(sd, Mapping) and len(sd) == 4
+    assert "iteration" in sd and sd["iteration"] == 0
+    assert "max_epochs" in sd and sd["max_epochs"] is None
+    assert "epoch_length" in sd and sd["epoch_length"] is None
+    assert "rng_states" in sd and sd["rng_states"] is not None