Michael Panchenko b900fdf6f2
Remove kwargs in policy init (#950)
Closes #947 

This removes all kwargs from all policy constructors. While doing that,
I also improved several names and added a whole lot of TODOs.

## Functional changes:

1. Added possibility to pass None as `critic2` and `critic2_optim`. In
fact, the default behavior then should cover the absolute majority of
cases
2. Added a function called `clone_optimizer` as a temporary measure to
support passing `critic2_optim=None`

## Breaking changes:

1. `action_space` is no longer optional. In fact, it already was
non-optional, as there was a ValueError in BasePolicy.init. So now
several examples were fixed to reflect that
2. `reward_normalization` removed from DDPG and children. It was never
allowed to pass it as `True` there, an error would have been raised in
`compute_n_step_reward`. Now I removed it from the interface
3. renamed `critic1` and similar to `critic`, in order to have uniform
interfaces. Note that the `critic` in DDPG was optional for the sole
reason that child classes used `critic1`. I removed this optionality
(DDPG can't do anything with `critic=None`)
4. Several renamings of fields (mostly private to public, so backwards
compatible)

## Additional changes: 
1. Removed type and default declaration from docstring. This kind of
duplication is really not necessary
2. Policy constructors are now only called using named arguments, not a
fragile mixture of positional and named as before
5. Minor beautifications in typing and code 
6. Generally shortened docstrings and made them uniform across all
policies (hopefully)

## Comment:

With these changes, several problems in tianshou's inheritance hierarchy
become more apparent. I tried highlighting them for future work.

---------

Co-authored-by: Dominik Jain <d.jain@appliedai.de>
2023-10-08 08:57:03 -07:00

45 lines
1.4 KiB
Python

from typing import Any
from torch import nn
from tianshou.data.types import RolloutBatchProtocol
from tianshou.policy import C51Policy
from tianshou.utils.net.discrete import NoisyLinear
# TODO: this is a hacky thing interviewing side-effects and a return. Should improve.
def _sample_noise(model: nn.Module) -> bool:
"""Sample the random noises of NoisyLinear modules in the model.
Returns True if at least one NoisyLinear submodule was found.
:param model: a PyTorch module which may have NoisyLinear submodules.
:returns: True if model has at least one NoisyLinear submodule;
otherwise, False.
"""
sampled_any_noise = False
for m in model.modules():
if isinstance(m, NoisyLinear):
m.sample()
sampled_any_noise = True
return sampled_any_noise
# TODO: is this class worth keeping? It barely does anything
class RainbowPolicy(C51Policy):
"""Implementation of Rainbow DQN. arXiv:1710.02298.
Same parameters as :class:`~tianshou.policy.C51Policy`.
.. seealso::
Please refer to :class:`~tianshou.policy.C51Policy` for more detailed
explanation.
"""
def learn(self, batch: RolloutBatchProtocol, *args: Any, **kwargs: Any) -> dict[str, float]:
_sample_noise(self.model)
if self._target and _sample_noise(self.model_old):
self.model_old.train() # so that NoisyLinear takes effect
return super().learn(batch, **kwargs)