IndexError when run the flow/envs/ring/lane_change_accel

[17150934]

when I run the flow/envs/ring/lane_change_accel,there is an error:

Traceback (most recent call last):
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/tune/trial_runner.py", line 426, in _process_trial
result = self.trial_executor.fetch_result(trial)
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/tune/ray_trial_executor.py", line 378, in fetch_result
result = ray.get(trial_future[0], DEFAULT_GET_TIMEOUT)
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/worker.py", line 1457, in get
raise value.as_instanceof_cause()
ray.exceptions.RayTaskError(IndexError): ray::PPO.train() (pid=5690, ip=192.168.6.112)
File "python/ray/_raylet.pyx", line 636, in ray._raylet.execute_task
File "python/ray/_raylet.pyx", line 619, in ray._raylet.execute_task.function_executor
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/rllib/agents/trainer.py", line 444, in train
raise e
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/rllib/agents/trainer.py", line 433, in train
result = Trainable.train(self)
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/tune/trainable.py", line 176, in train
result = self._train()
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/rllib/agents/trainer_template.py", line 129, in _train
fetches = self.optimizer.step()
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/rllib/optimizers/multi_gpu_optimizer.py", line 140, in step
self.num_envs_per_worker, self.train_batch_size)
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/rllib/optimizers/rollout.py", line 29, in collect_samples
next_sample = ray_get_and_free(fut_sample)
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/rllib/utils/memory.py", line 33, in ray_get_and_free
result = ray.get(object_ids)
ray.exceptions.RayTaskError(IndexError): ray::RolloutWorker.sample() (pid=5766, ip=192.168.6.112)
File "python/ray/_raylet.pyx", line 636, in ray._raylet.execute_task
File "python/ray/_raylet.pyx", line 619, in ray._raylet.execute_task.function_executor
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/rllib/evaluation/rollout_worker.py", line 471, in sample
batches = [self.input_reader.next()]
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/rllib/evaluation/sampler.py", line 56, in next
batches = [self.get_data()]
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/rllib/evaluation/sampler.py", line 99, in get_data
item = next(self.rollout_provider)
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/rllib/evaluation/sampler.py", line 340, in _env_runner
base_env.send_actions(actions_to_send)
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/rllib/env/base_env.py", line 332, in send_actions
self.vector_env.vector_step(action_vector)
File "/home/vcdc/anaconda3/envs/flow/lib/python3.7/site-packages/ray/rllib/env/vector_env.py", line 110, in vector_step
obs, r, done, info = self.envs[i].step(actions[i])
File "/home/vcdc/flow/flow/envs/base.py", line 364, in step
self.apply_rl_actions(rl_actions)
File "/home/vcdc/flow/flow/envs/base.py", line 616, in apply_rl_actions
self._apply_rl_actions(rl_clipped)
File "/home/vcdc/flow/flow/envs/ring/lane_change_accel.py", line 151, in _apply_rl_actions
np.array([0] * sum(non_lane_changing_veh))
IndexError: boolean index did not match indexed array along dimension 0; dimension is 0 but corresponding boolean dimension is 1

i do not know what the code(

non_lane_changing_veh =
[self.time_counter <=
self.env_params.additional_params["lane_change_duration"]
+ self.k.vehicle.get_last_lc(veh_id)
for veh_id in sorted_rl_ids]

) means,because non_lane_changing_veh does not look like an integer. Anybody tell me what is wrong, I think the code is not correct