"""HPI: Homotopy-Based Policy Iteration for Adaptive Optimal Control.

Implements the algorithm from:
  Chen et al., "Adaptive Optimal Control of Unknown Nonlinear Systems
  via Homotopy-Based Policy Iteration", IEEE TAC, 2024.

Uses neural network function approximators (CriticNN, ActorNN) trained
via gradient-based Bellman residual minimization.
"""

from .nn_models import (ActorNN, CriticNN, check_lyapunov_decrease,
                        check_positive_definite, compute_q)
from .data_collector import DataCollector
from .nn_trainer import NNTrainer
from .hpi_controller import HPIController

__all__ = [
    "CriticNN",
    "ActorNN",
    "compute_q",
    "check_positive_definite",
    "check_lyapunov_decrease",
    "DataCollector",
    "NNTrainer",
    "HPIController",
]