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- from gym.spaces import Discrete, Space
- from typing import Union, Optional
- from ray.rllib.models.action_dist import ActionDistribution
- from ray.rllib.models.tf.tf_action_dist import Categorical
- from ray.rllib.models.torch.torch_action_dist import TorchCategorical
- from ray.rllib.utils.annotations import override
- from ray.rllib.utils.exploration.stochastic_sampling import StochasticSampling
- from ray.rllib.utils.framework import TensorType
- class SoftQ(StochasticSampling):
- """Special case of StochasticSampling w/ Categorical and temperature param.
- Returns a stochastic sample from a Categorical parameterized by the model
- output divided by the temperature. Returns the argmax iff explore=False.
- """
- def __init__(self,
- action_space: Space,
- *,
- framework: Optional[str],
- temperature: float = 1.0,
- **kwargs):
- """Initializes a SoftQ Exploration object.
- Args:
- action_space (Space): The gym action space used by the environment.
- temperature (float): The temperature to divide model outputs by
- before creating the Categorical distribution to sample from.
- framework (str): One of None, "tf", "torch".
- """
- assert isinstance(action_space, Discrete)
- super().__init__(action_space, framework=framework, **kwargs)
- self.temperature = temperature
- @override(StochasticSampling)
- def get_exploration_action(self,
- action_distribution: ActionDistribution,
- timestep: Union[int, TensorType],
- explore: bool = True):
- cls = type(action_distribution)
- assert cls in [Categorical, TorchCategorical]
- # Re-create the action distribution with the correct temperature
- # applied.
- dist = cls(
- action_distribution.inputs,
- self.model,
- temperature=self.temperature)
- # Delegate to super method.
- return super().get_exploration_action(
- action_distribution=dist, timestep=timestep, explore=explore)
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