Question Pytorch error: Class values must be smaller than num_classes

After about 20 seconds of training my agent, I get this error in the Anaconda command prompt. The Unity editor and game keep running but I don't know what kind of training is being done. In either case, I'd like to find out what the error is. I tried doing different actions within the game to trigger it, but it seems to happen no matter what at around 20 seconds in.

Even when I stop the game within Editor, python.exe keeps running and has to be closed within Task Manager. The trace below is from after I stopped python. If I didn't it wouldn't get past the 'RuntimeError' line.

I'm using ml agents 1.9.0, Windows 7 64-bit, Anaconda3, Unity 2020-3-0f1. I am also noob.

The full terminal trace is:

Code (CSharp):

1.  
2. (mlagents-r8) E:\Programming\Unity Hub\My projects\Rocket Ball wAI>mlagents-lear
3. n Configs\PlayRocketBallConfig.yaml --time-scale 0.02 --target-frame-rate 60 --r
4. un-id P2AIAtt12 --force
5.  
6. (Unity logo)
7.  
8. Version information:
9.   ml-agents: 0.25.0,
10.   ml-agents-envs: 0.25.0,
11.   Communicator API: 1.5.0,
12.   PyTorch: 1.8.0
13. 2021-04-08 14:15:08 INFO [learn.py:245] run_seed set to 7998
14. 2021-04-08 14:15:08 INFO [torch.py:58] default Torch device: cuda
15. 2021-04-08 14:15:10 INFO [environment.py:210] Listening on port 5004. Start trai
16. ning by pressing the Play button in the Unity Editor.
17. 2021-04-08 14:15:16 INFO [environment.py:112] Connected to Unity environment wit
18. h package version 1.9.0-preview and communication version 1.5.0
19. 2021-04-08 14:15:16 INFO [environment.py:282] Connected new brain:
20. P2AIAtt?team=0
21. 2021-04-08 14:15:16 WARNING [stats.py:237] events.out.tfevents.1617882358.TurNam
22. e-PC.6608.0 was left over from a previous run. Deleting.
23. 2021-04-08 14:15:16 INFO [stats.py:186] Hyperparameters for behavior name P2AIAt
24. t:
25.         trainer_type:   ppo
26.         hyperparameters:
27.           batch_size:   10
28.           buffer_size:  100
29.           learning_rate:        0.0003
30.           beta: 0.0005
31.           epsilon:      0.2
32.           lambd:        0.99
33.           num_epoch:    3
34.           learning_rate_schedule:       linear
35.         network_settings:
36.           normalize:    False
37.           hidden_units: 128
38.           num_layers:   2
39.           vis_encode_type:      simple
40.           memory:       None
41.         reward_signals:
42.           extrinsic:
43.             gamma:      0.99
44.             strength:   1.0
45.             network_settings:
46.               normalize:        False
47.               hidden_units:     128
48.               num_layers:       2
49.               vis_encode_type:  simple
50.               memory:   None
51.           gail:
52.             gamma:      0.99
53.             strength:   0.5
54.             network_settings:
55.               normalize:        False
56.               hidden_units:     128
57.               num_layers:       2
58.               vis_encode_type:  simple
59.               memory:   None
60.             learning_rate:      0.0003
61.             encoding_size:      None
62.             use_actions:        False
63.             use_vail:   False
64.             demo_path:  Demos\PlayRocketBall_0.demo
65.         init_path:      None
66.         keep_checkpoints:       5
67.         checkpoint_interval:    500000
68.         max_steps:      500000
69.         time_horizon:   64
70.         summary_freq:   10000
71.         threaded:       True
72.         self_play:      None
73.         behavioral_cloning:
74.           demo_path:    Demos\PlayRocketBall_0.demo
75.           steps:        0
76.           strength:     0.5
77.           samples_per_update:   0
78.           num_epoch:    None
79.           batch_size:   None
80. Exception in thread Thread-2:
81. Traceback (most recent call last):
82.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\threading.py", line 932, i
83. n _bootstrap_inner
84.     self.run()
85.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\threading.py", line 870, i
86. n run
87.     self._target(*self._args, **self._kwargs)
88.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\site-packages\mlagents\tra
89. iners\trainer_controller.py", line 297, in trainer_update_func
90.     trainer.advance()
91.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\site-packages\mlagents\tra
92. iners\trainer\rl_trainer.py", line 297, in advance
93.     if self._update_policy():
94.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\site-packages\mlagents\tra
95. iners\ppo\trainer.py", line 213, in _update_policy
96.     update_stats = self.optimizer.bc_module.update()
97.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\site-packages\mlagents\tra
98. iners\torch\components\bc\module.py", line 93, in update
99.     run_out = self._update_batch(mini_batch_demo, self.n_sequences)
100.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\site-packages\mlagents\tra
101. iners\torch\components\bc\module.py", line 175, in _update_batch
102.     bc_loss = self._behavioral_cloning_loss(
103.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\site-packages\mlagents\tra
104. iners\torch\components\bc\module.py", line 116, in _behavioral_cloning_loss
105.     one_hot_expert_actions = ModelUtils.actions_to_onehot(
106.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\site-packages\mlagents\tra
107. iners\torch\utils.py", line 275, in actions_to_onehot
108.     onehot_branches = [
109.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\site-packages\mlagents\tra
110. iners\torch\utils.py", line 276, in <listcomp>
111.     torch.nn.functional.one_hot(_act.T, action_size[i]).float()
112. RuntimeError: Class values must be smaller than num_classes.
113. 2021-04-08 14:15:54 INFO [subprocess_env_manager.py:220] UnityEnvironment worker
114. 0: environment stopping.
115. 2021-04-08 14:15:54 INFO [trainer_controller.py:187] Learning was interrupted. P
116. lease wait while the graph is generated.
117. 2021-04-08 14:15:56 INFO [model_serialization.py:183] Converting to results\P2AI
118. Att12\P2AIAtt\P2AIAtt-128.onnx
119. 2021-04-08 14:16:00 INFO [model_serialization.py:195] Exported results\P2AIAtt12
120. \P2AIAtt\P2AIAtt-128.onnx
121. 2021-04-08 14:16:00 INFO [torch_model_saver.py:116] Copied results\P2AIAtt12\P2A
122. IAtt\P2AIAtt-128.onnx to results\P2AIAtt12\P2AIAtt.onnx.
123. 2021-04-08 14:16:00 INFO [trainer_controller.py:81] Saved Model

Update:
If I keep playing in the Editor despite the error, after about 2 minutes of play, the editor freezes. If I stop python.exe again in Task Manager, I get control back and in the anaconda prompt I get these additional errors, which being right after 'Runtime Error' above

Code (CSharp):

1.  
2. 2021-04-08 17:40:54 ERROR [subprocess_env_manager.py:226] UnityEnvironment worke
3. r 0: environment raised an unexpected exception.
4. Traceback (most recent call last):
5.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\multiprocessing\connection
6. .py", line 312, in _recv_bytes
7.     nread, err = ov.GetOverlappedResult(True)
8. BrokenPipeError: [WinError 109] The pipe has been ended
9.  
10. During handling of the above exception, another exception occurred:
11.  
12. Traceback (most recent call last):
13.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\site-packages\mlagents\tra
14. iners\subprocess_env_manager.py", line 172, in worker
15.     req: EnvironmentRequest = parent_conn.recv()
16.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\multiprocessing\connection
17. .py", line 250, in recv
18.     buf = self._recv_bytes()
19.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\multiprocessing\connection
20. .py", line 321, in _recv_bytes
21.     raise EOFError
22. EOFError
23. Process Process-1:
24. Traceback (most recent call last):
25.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\multiprocessing\connection
26. .py", line 312, in _recv_bytes
27.     nread, err = ov.GetOverlappedResult(True)
28. BrokenPipeError: [WinError 109] The pipe has been ended
29.  
30. During handling of the above exception, another exception occurred:
31.  
32. Traceback (most recent call last):
33.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\site-packages\mlagents\tra
34. iners\subprocess_env_manager.py", line 172, in worker
35.     req: EnvironmentRequest = parent_conn.recv()
36.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\multiprocessing\connection
37. .py", line 250, in recv
38.     buf = self._recv_bytes()
39.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\multiprocessing\connection
40. .py", line 321, in _recv_bytes
41.     raise EOFError
42. EOFError
43.  
44. During handling of the above exception, another exception occurred:
45.  
46. Traceback (most recent call last):
47.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\multiprocessing\process.py
48. ", line 315, in _bootstrap
49.     self.run()
50.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\multiprocessing\process.py
51. ", line 108, in run
52.     self._target(*self._args, **self._kwargs)
53.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\site-packages\mlagents\tra
54. iners\subprocess_env_manager.py", line 232, in worker
55.     _send_response(EnvironmentCommand.ENV_EXITED, ex)
56.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\site-packages\mlagents\tra
57. iners\subprocess_env_manager.py", line 147, in _send_response
58.     parent_conn.send(EnvironmentResponse(cmd_name, worker_id, payload))
59.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\multiprocessing\connection
60. .py", line 206, in send
61.     self._send_bytes(_ForkingPickler.dumps(obj))
62.   File "e:\programming\anaconda3\envs\mlagents-r8\lib\multiprocessing\connection
63. .py", line 280, in _send_bytes
64.     ov, err = _winapi.WriteFile(self._handle, buf, overlapped=True)
65. BrokenPipeError: [WinError 232] The pipe is being closed

In the VSCode debugger, if I hit pause while the editor is frozen, it takes me to E:\Programming\Unity Hub\My projects\Rocket Ball wAI\Library\PackageCache\com.unity.ml-agents@1.9.0-preview\Runtime\Grpc\CommunicatorObjects\UnityToExternalGrpc.cs line 90, the whole function being the following:

Code (CSharp):

1.  
2. public virtual global::Unity.MLAgents.CommunicatorObjects.UnityMessageProto Exchange(global::Unity.MLAgents.CommunicatorObjects.UnityMessageProto request, grpc::CallOptions options)
3.       {
4.         return CallInvoker.BlockingUnaryCall(__Method_Exchange, null, options, request);
5.       }

 

So, I have narrowed it down to the Demonstration Recorder and the Buffer Size in parameters. When I don't have behavioral cloning or gail in the config file, I don't get the error. And when I increase buffer size, the error takes longer to occur. I don't understand buffer sizes well enough to be able to stop the error completely though.