Added Polyak update rate for soft DQN target network updates

manjavacas commented 1 year ago

Description

According to #346, the Polyak update rate (tau) has been included as an argument to dqn.py and dqn_atari.py implementations.

It will allow soft updates of the target network, as already done for dqn_jax.py.

Types of changes

[ ] Bug fix
[x] New feature
[ ] New algorithm
[x] Documentation

Checklist:

[x] I've read the CONTRIBUTION guide (required).
[x] I have ensured pre-commit run --all-files passes (required).
[x] I have updated the documentation and previewed the changes via mkdocs serve.
[ ] I have updated the tests accordingly (if applicable).

If you are adding new algorithm variants or your change could result in performance difference, you may need to (re-)run tracked experiments. See https://github.com/vwxyzjn/cleanrl/pull/137 as an example PR.

[ ] I have contacted vwxyzjn to obtain access to the openrlbenchmark W&B team (required).
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[ ] I have added additional documentation and previewed the changes via mkdocs serve.
- [ ] I have explained note-worthy implementation details.
- [ ] I have explained the logged metrics.
- [ ] I have added links to the original paper and related papers (if applicable).
- [ ] I have added links to the PR related to the algorithm variant.
- [ ] I have created a table comparing my results against those from reputable sources (i.e., the original paper or other reference implementation).
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[ ] I have updated the tests accordingly (if applicable).