'Observation outside expected value range' error when running example 'traffic_light_grid.py'

Question

I'm trying to learn how to use FLOW. When I was trying to run 'flow/example/rllib/traffic_light_grid.py', it kept returning 'Observation outside expected value range' errors, until it reached the maximum error number. I have no idea why only this example went wrong while other examples worked. Can anyone help me with that? An error example is as shown below:

  ERROR trial_runner.py:550 -- Error processing event.
    next_sample = ray_get_and_free(fut_sample)
  File "/home/ming/miniconda3/envs/flow/lib/python3.6/site-packages/ray/rllib/utils/memory.py", line 33, in ray_get_and_free
    result = ray.get(object_ids)
  ray.exceptions.RayTaskError: ray_RolloutWorker:sample() (pid=6597, host=VirtualBox)
  File "/home/ming/miniconda3/envs/flow/lib/python3.6/site-packages/ray/rllib/evaluation/rollout_worker.py", line 453, in sample
    batches = [self.input_reader.next()]
  File "/home/ming/miniconda3/envs/flow/lib/python3.6/site-packages/ray/rllib/evaluation/sampler.py", line 56, in next
    batches = [self.get_data()]
  File "/home/ming/miniconda3/envs/flow/lib/python3.6/site-packages/ray/rllib/evaluation/sampler.py", line 97, in get_data
    item = next(self.rollout_provider)
  File "/home/ming/miniconda3/envs/flow/lib/python3.6/site-packages/ray/rllib/evaluation/sampler.py", line 313, in _env_runner
    soft_horizon)
  File "/home/ming/miniconda3/envs/flow/lib/python3.6/site-packages/ray/rllib/evaluation/sampler.py", line 401, in _process_observations
    policy_id).transform(raw_obs)
  File "/home/ming/miniconda3/envs/flow/lib/python3.6/site-packages/ray/rllib/models/preprocessors.py", line 166, in transform
    self.check_shape(observation)
  File "/home/ming/miniconda3/envs/flow/lib/python3.6/site-packages/ray/rllib/models/preprocessors.py", line 61, in check_shape
    self._obs_space, observation)
ValueError: ('Observation outside expected value range', Box(339,), array([0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.05      , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.42857143, 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 0.        , 0.        , 0.        ,
       0.        , 0.        , 1.        , 0.        , 3.        ,
       1.        , 1.        , 3.        , 3.        , 0.        ,
       0.        , 1.        , 0.        , 0.        , 1.        ,
       0.        , 0.        , 1.        , 0.        , 0.        ,
       1.        , 1.        , 0.        , 1.        , 1.        ,
       0.        , 0.        , 1.        , 1.        ]))

My SUMO version is v1_1_0+0000-2147d155b1

Thanks

This bug is because the observations aren't normalized correctly. This is fixed on the master branch if you just pull it. — Eugene Vinitsky, Dec 01 '19 at 06:53

score 0 · Answer 1 · answered Jun 09 '21 at 09:04

check the file under flow/flow/envs/merge.py or some others. There is a function named

@property
def observation_space(self):
    """See class definition."""
    return Box(low=-1000, high=1000, shape=(5 * self.num_rl, ), dtype=np.float32)

set the low to -1000 and the high to 1000

'Observation outside expected value range' error when running example 'traffic_light_grid.py'

1 Answers1