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A2C playing BreakoutNoFrameskip-v4 from https://github.com/sgoodfriend/rl-algo-impls/tree/0760ef7d52b17f30219a27c18ba52c8895025ae3
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import gym
import torch as th
import torch.nn as nn
from gym.spaces import Discrete
from typing import Optional, Sequence, Type
from shared.module.feature_extractor import FeatureExtractor
from shared.module.module import mlp
class QNetwork(nn.Module):
def __init__(
self,
observation_space: gym.Space,
action_space: gym.Space,
hidden_sizes: Sequence[int] = [],
activation: Type[nn.Module] = nn.ReLU, # Used by stable-baselines3
cnn_feature_dim: int = 512,
cnn_style: str = "nature",
cnn_layers_init_orthogonal: Optional[bool] = None,
impala_channels: Sequence[int] = (16, 32, 32),
) -> None:
super().__init__()
assert isinstance(action_space, Discrete)
self._feature_extractor = FeatureExtractor(
observation_space,
activation,
cnn_feature_dim=cnn_feature_dim,
cnn_style=cnn_style,
cnn_layers_init_orthogonal=cnn_layers_init_orthogonal,
impala_channels=impala_channels,
)
layer_sizes = (
(self._feature_extractor.out_dim,) + tuple(hidden_sizes) + (action_space.n,)
)
self._fc = mlp(layer_sizes, activation)
def forward(self, obs: th.Tensor) -> th.Tensor:
x = self._feature_extractor(obs)
return self._fc(x)