# Copyright 2024 The HuggingFace Inc. team. All rights reserved.
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# Licensed under the Apache License, Version 2.0 (the "License");
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#     http://www.apache.org/licenses/LICENSE-2.0
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import os
from dataclasses import dataclass
from typing import Optional

from trl.trainer.utils import OnPolicyConfig


@dataclass
class PPOConfig(OnPolicyConfig):
    r"""
    Configuration class for the [`PPOTrainer`].

    Using [`~transformers.HfArgumentParser`] we can turn this class into
    [argparse](https://docs.python.org/3/library/argparse#module-argparse) arguments that can be specified on the
    command line.

    Parameters:
        exp_name (`str`, *optional*, defaults to `os.path.basename(__file__)[:-3]`):
            Name of this experiment.
        reward_model_path (`str`, *optional*, defaults to `"EleutherAI/pythia-160m"`):
            Path to the reward model.
        model_adapter_name (`Optional[str]`, *optional*, defaults to `None`):
            Name of the train target PEFT adapter, when using LoRA with multiple adapters.
        ref_adapter_name (`Optional[str]`, *optional*, defaults to `None`):
            Name of the reference PEFT adapter, when using LoRA with multiple adapters.
        num_ppo_epochs (`int`, *optional*, defaults to `4`):
            Number of epochs to train.
        whiten_rewards (`bool`, *optional*, defaults to `False`):
            Whether to whiten the rewards.
        kl_coef (`float`, *optional*, defaults to `0.05`):
            KL coefficient.
        cliprange (`float`, *optional*, defaults to `0.2`):
            Clip range.
        vf_coef (`float`, *optional*, defaults to `0.1`):
            Value function coefficient.
        cliprange_value (`float`, *optional*, defaults to `0.2`):
            Clip range for the value function.
        gamma (`float`, *optional*, defaults to `1.0`):
            Discount factor.
        lam (`float`, *optional*, defaults to `0.95`):
            Lambda value for GAE.
    """

    exp_name: str = os.path.basename(__file__)[: -len(".py")]
    reward_model_path: str = "EleutherAI/pythia-160m"
    value_model_path: str = "EleutherAI/pythia-160m"
    model_adapter_name: Optional[str] = None
    ref_adapter_name: Optional[str] = None
    num_ppo_epochs: int = 4
    whiten_rewards: bool = False
    kl_coef: float = 0.05
    cliprange: float = 0.2
    vf_coef: float = 0.1
    cliprange_value: float = 0.2
    gamma: float = 1.0
    lam: float = 0.95