stable-baselines3-contrib-sacd/docs/modules/ars.rst

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.. _ars:
.. automodule:: sb3_contrib.ars
ARS
===
Augmented Random Search (ARS) is a simple reinforcement algorithm that uses a direct random search over policy
parameters. It can be surprisingly effective compared to more sophisticated algorithms. In the `original paper <https://arxiv.org/abs/1803.07055>`_ the authors showed that linear policies trained with ARS were competitive with deep reinforcement learning for the MuJuCo locomotion tasks.
SB3s implementation allows for linear policies without bias or squashing function, it also allows for training MLP policies, which include linear policies with bias and squashing functions as a special case.
Normally one wants to train ARS with several seeds to properly evaluate.
.. warning::
ARS multi-processing is different from the classic Stable-Baselines3 multi-processing: it runs n environments
in parallel but asynchronously. This asynchronous multi-processing is considered experimental
and does not fully support callbacks: the ``on_step()`` event is called artificially after the evaluation episodes are over.
.. rubric:: Available Policies
.. autosummary::
:nosignatures:
LinearPolicy
MlpPolicy
Notes
-----
- Original paper: https://arxiv.org/abs/1803.07055
- Original Implementation: https://github.com/modestyachts/ARS
Can I use?
----------
- Recurrent policies: ❌
- Multi processing: ✔️ (cf. example)
- Gym spaces:
============= ====== ===========
Space Action Observation
============= ====== ===========
Discrete ✔️ ✔️
Box ✔️ ✔️
MultiDiscrete ❌ ✔️
MultiBinary ❌ ✔️
Dict ❌ ❌
============= ====== ===========
Example
-------
.. code-block:: python
from sb3_contrib import ARS
# Policy can be LinearPolicy or MlpPolicy
model = ARS("LinearPolicy", "Pendulum-v0", verbose=1)
model.learn(total_timesteps=10000, log_interval=4)
model.save("ars_pendulum")
With experimental asynchronous multi-processing:
.. code-block:: python
from sb3_contrib import ARS
from sb3_contrib.common.vec_env import AsyncEval
from stable_baselines3.common.env_util import make_vec_env
env_id = "CartPole-v1"
n_envs = 2
model = ARS("LinearPolicy", env_id, n_delta=2, n_top=1, verbose=1)
# Create env for asynchronous evaluation (run in different processes)
async_eval = AsyncEval([lambda: make_vec_env(env_id) for _ in range(n_envs)], model.policy)
model.learn(total_timesteps=200_000, log_interval=4, async_eval=async_eval)
Results
-------
Replicating results from the original paper, which used the Mujoco benchmarks. Same parameters from the original paper, using 8 seeds.
============= ============
Environments ARS
============= ============
\
HalfCheetah 4398 +/- 320
Swimmer 241 +/- 51
Hopper 3320 +/- 120
============= ============
How to replicate the results?
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Clone RL-Zoo and checkout the branch ``feat/ars``
.. code-block:: bash
git clone https://github.com/DLR-RM/rl-baselines3-zoo
cd rl-baselines3-zoo/
git checkout feat/ars
Run the benchmark. The following code snippet trains 8 seeds in parallel
.. code-block:: bash
for ENV_ID in Swimmer-v3 HalfCheetah-v3 Hopper-v3
do
for SEED_NUM in {1..8}
do
SEED=$RANDOM
python train.py --algo ars --env $ENV_ID --eval-episodes 10 --eval-freq 10000 -n 20000000 --seed $SEED &
sleep 1
done
wait
done
Plot the results:
.. code-block:: bash
python scripts/all_plots.py -a ars -e HalfCheetah Swimmer Hopper -f logs/ -o logs/ars_results -max 20000000
python scripts/plot_from_file.py -i logs/ars_results.pkl -l ARS
Parameters
----------
.. autoclass:: ARS
:members:
:inherited-members:
.. _ars_policies:
ARS Policies
-------------
.. autoclass:: sb3_contrib.ars.policies.ARSPolicy
:members:
:noindex:
.. autoclass:: LinearPolicy
:members:
:inherited-members:
.. autoclass:: MlpPolicy
:members: