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2026-07-13 13:17:40 +08:00

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Python

"""
TQC Learner base class.
Extends SAC Learner with quantile-specific loss computation.
"""
from ray.rllib.algorithms.sac.sac_learner import SACLearner
from ray.rllib.core.learner.learner import Learner
from ray.rllib.utils.annotations import override
from ray.rllib.utils.typing import ModuleID
# Loss keys for TQC
QF_LOSS_KEY = "qf_loss"
QF_MEAN_KEY = "qf_mean"
QF_MAX_KEY = "qf_max"
QF_MIN_KEY = "qf_min"
QUANTILES_KEY = "quantiles"
TD_ERROR_MEAN_KEY = "td_error_mean"
class TQCLearner(SACLearner):
"""Base Learner class for TQC algorithm.
TQC extends SAC with distributional critics using quantile regression.
The main differences are:
- Uses quantile Huber loss instead of standard Huber/MSE loss
- Computes target Q-values by sorting and truncating top quantiles
"""
@override(Learner)
def build(self) -> None:
"""Builds the TQC learner."""
# Call parent build (handles alpha/entropy coefficient)
super().build()
def _get_n_target_quantiles(self, module_id: ModuleID) -> int:
"""Returns the number of target quantiles after truncation.
Args:
module_id: The module ID.
Returns:
Number of quantiles to use for target computation.
"""
config = self.config.get_config_for_module(module_id)
n_quantiles = config.n_quantiles
n_critics = config.n_critics
top_quantiles_to_drop = config.top_quantiles_to_drop_per_net
total_quantiles = n_quantiles * n_critics
quantiles_to_drop = top_quantiles_to_drop * n_critics
return total_quantiles - quantiles_to_drop