# Inconsistent number of episodes with 'evaluate'

**URL:** <https://discuss.ray.io/t/inconsistent-number-of-episodes-with-evaluate/6784>\
**Category:** RLlib\
**Created:** [July 11, 2022, 11:51am UTC](https://discuss.ray.io/t/inconsistent-number-of-episodes-with-evaluate/6784 "2022-07-11T11:51:26Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![leo593](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/leo593/32/2690_2.png) [@leo593](https://discuss.ray.io/u/leo593)\
**Post date:** [July 11, 2022, 11:51am UTC](https://discuss.ray.io/t/inconsistent-number-of-episodes-with-evaluate/6784/1 "2022-07-11T11:51:26Z")

</div>

**How severe does this issue affect your experience of using Ray?**

- Low: It annoys or frustrates me for a moment.

Hi!

I noticed a strange behavior with `rllib evaluate` in command line: depending on the environment, the number of evaluation episodes requested in the command line never get reached during the evaluation.

For example, running `rllib evaluate <chkpt_path> --run PPO --env CartPole-v0 --episodes 100` will only run about 50-55 evaluation episodes (no matter the number of episodes requested in the command line as long as it is \>55). I have the same problem with other environments/algorithms (but each time a different “max” number of episodes)

Here is a reproduction script:

```auto
import ray
from ray import tune
import gym
import os

ray.tune.run(
    'PPO',
    stop={
        'training_iteration': 50,
    },
    config={'env':'CartPole-v0'},
    checkpoint_freq=25,
    checkpoint_score_attr='episode_reward_mean',
    checkpoint_at_end=True,
    local_dir='checkpoint',
)

os.chdir('checkpoint/PPO')
folders=os.listdir('.')
result=[]
for filename in folders:
    if os.path.isdir(os.path.join(os.path.abspath('.'), filename)):
        result.append(filename)
chkpt_dir = max(result, key=os.path.getmtime)

os.system('rllib evaluate '+chkpt_dir+'/checkpoint_000050/checkpoint-50 --run PPO --env CartPole-v0 --episodes 200')

```

---

<div class="post-metadata">

**Author:** ![Lars\_Simon\_Zehnder](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/lars_simon_zehnder/32/1185_2.png) [@Lars\_Simon\_Zehnder](https://discuss.ray.io/u/Lars_Simon_Zehnder)\
**Post date:** [July 12, 2022, 5:31pm UTC](https://discuss.ray.io/t/inconsistent-number-of-episodes-with-evaluate/6784/2 "2022-07-12T17:31:48Z")

</div>

Hi @leo593,  
I can replicate this. Looking into the èavluate.py` script it might mak sense:

```auto
parser.add_argument(
        "--steps",
        default=10000,
        help="Number of timesteps to roll out. Rollout will also stop if "
        "`--episodes` limit is reached first. A value of 0 means no "
        "limitation on the number of timesteps run.",
    )
    parser.add_argument(
        "--episodes",
        default=0,
        help="Number of complete episodes to roll out. Rollout will also stop "
        "if `--steps` (timesteps) limit is reached first. A value of 0 means "
        "no limitation on the number of episodes run.",
    )

```

Could it be that the number of timesteps has reached 10,000 after 50 episodes?

---

<div class="post-metadata">

**Author:** ![leo593](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/leo593/32/2690_2.png) [@leo593](https://discuss.ray.io/u/leo593)\
**Post date:** [July 18, 2022, 1:58pm UTC](https://discuss.ray.io/t/inconsistent-number-of-episodes-with-evaluate/6784/3 "2022-07-18T13:58:55Z")

</div>

Hi @Lars_Simon_Zehnder thank you for your help, you’re right ! It makes sense now 🙂