# How to parallelize training multiple models

**URL:** <https://discuss.ray.io/t/how-to-parallelize-training-multiple-models/1396>\
**Category:** Ray Tune\
**Created:** [March 25, 2021, 5:40pm UTC](https://discuss.ray.io/t/how-to-parallelize-training-multiple-models/1396 "2021-03-25T17:40:53Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![Rajesh\_Chawla](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/rajesh_chawla/32/383_2.png) [@Rajesh\_Chawla](https://discuss.ray.io/u/Rajesh_Chawla)\
**Post date:** [March 25, 2021, 5:40pm UTC](https://discuss.ray.io/t/how-to-parallelize-training-multiple-models/1396/1 "2021-03-25T17:40:53Z")

</div>

I’m working to learn RLlib / Tune / Ray and I could use advice on how to approach my use case.

I currently train a model using Tune.run. Now, I’d like to train 40 to 50 models for different settings using my custom gym environment.

My current approach is training the models one at a time by invoking Tune.run in a loop, changing the parameter setting for each training run.

Is there an approach where I could parallelize the training of models ?

Regards,  
Rajesh

---

<div class="post-metadata">

**Author:** ![eoakes](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/eoakes/32/7825_2.png) [@eoakes](https://discuss.ray.io/u/eoakes)\
**Post date:** [March 26, 2021, 2:40am UTC](https://discuss.ray.io/t/how-to-parallelize-training-multiple-models/1396/2 "2021-03-26T02:40:41Z")

</div>

@rliaw @kai could you provide a pointer here?

---

<div class="post-metadata">

**Author:** ![rliaw](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/rliaw/32/24_2.png) [@rliaw](https://discuss.ray.io/u/rliaw)\
**Post date:** [March 26, 2021, 6:59am UTC](https://discuss.ray.io/t/how-to-parallelize-training-multiple-models/1396/3 "2021-03-26T06:59:48Z")

</div>

Can you set the parameter settings as a Tune hyperparameter space?

[https://docs.ray.io/en/master/tune/api\_docs/suggestion.html#tune-basicvariant](https://docs.ray.io/en/master/tune/api_docs/suggestion.html#tune-basicvariant)

---

<div class="post-metadata">

**Author:** ![Rajesh\_Chawla](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/rajesh_chawla/32/383_2.png) [@Rajesh\_Chawla](https://discuss.ray.io/u/Rajesh_Chawla)\
**Post date:** [March 30, 2021, 2:38pm UTC](https://discuss.ray.io/t/how-to-parallelize-training-multiple-models/1396/4 "2021-03-30T14:38:55Z")

</div>

In working to use this suggestion, I’d like to pass in parameters to my custom environment. When I try this, ( see code at end ), I end up with a TypeError.

My question is: What is the correct way to pass information to the custom environment?

Regards,  
Rajesh

My call for tune.run():

```auto
analysis = tune.run(
    "PPO",
    name="{}_{}_ray_{}_tf_{}".format(
        timelog, "PPO", ray. __version__ , tf. __version__ ),
    num_samples=num_samples,
    metric="episode_reward_mean",
    checkpoint_freq=1,
    checkpoint_score_attr="episode_reward_mean",
    mode="max",
    verbose=1,
    stop={"training_iteration": 50},
    search_alg=BasicVariantGenerator(points_to_evaluate=[
        {"env_config": {2, 11, 0.0, 0.3, 0.7, 30}},

    ]),
    config=config)

```

The error:

```auto
ray.exceptions.RayTaskError(TypeError): ray::RolloutWorker.foreach_policy() (pid=18184, ip=10.0.1.2)
  File "python/ray/_raylet.pyx", line 439, in ray._raylet.execute_task
  File "python/ray/_raylet.pyx", line 473, in ray._raylet.execute_task
  File "python/ray/_raylet.pyx", line 476, in ray._raylet.execute_task
  File "python/ray/_raylet.pyx", line 480, in ray._raylet.execute_task
  File "python/ray/_raylet.pyx", line 432, in ray._raylet.execute_task.function_executor
  File "/home/opc/mlenv/lib64/python3.6/site-packages/ray/rllib/evaluation/rollout_worker.py", line 347, in __init__
    env_config or {}, worker_index, num_workers=num_workers)
  File "/home/opc/mlenv/lib64/python3.6/site-packages/ray/rllib/env/env_context.py", line 31, in __init__
    dict. __init__ (self, env_config)
TypeError: cannot convert dictionary update sequence element #0 to a sequence

```

---

<div class="post-metadata">

**Author:** ![rliaw](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ray.io/rliaw/32/24_2.png) [@rliaw](https://discuss.ray.io/u/rliaw)\
**Post date:** [April 5, 2021, 10:30pm UTC](https://discuss.ray.io/t/how-to-parallelize-training-multiple-models/1396/5 "2021-04-05T22:30:26Z")

</div>

> [@Rajesh\_Chawla](#):
>
> `env_config`

Hmm, could you show me the example of what you’re trying to do without the BasicVariantGenerator?