unsloth_compiled_cache/UnslothRLOOTrainer.py

"""
2026.6.7
2026.6.9
5.5.0
1.7.0
__UNSLOTH_VERSIONING__
"""

# Unsloth auto generated code
# Copyright 2023-present Daniel Han-Chen, Michael Han-Chen & the Unsloth team. All rights reserved.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

from torch import Tensor
import torch
import torch.nn as nn
from torch.nn import functional as F
from unsloth_zoo.temporary_patches.common import torch_compile
from typing import Any, List, Optional, Tuple, Union, Dict, Set, Callable
from trl.trainer.rloo_trainer import (Any, AutoModelForSequenceClassification, AutoProcessor, AutoTokenizer, Dataset, DistributedBackend, GenerationConfig, IterableDataset, LoraConfig, Path, PeftConfig, PeftModel, PreTrainedModel, PreTrainedTokenizerBase, ProcessorMixin, RLOOConfig, RLOOTrainer, RepeatSampler, RewardFunc, Sampler, SyncRefModelCallback, TrainerCallback, VLLMGeneration, Version, _BaseTrainer, apply_chat_template, asyncio, atexit, copy, create_model_from_path, defaultdict, deque, disable_dropout_in_model, disable_gradient_checkpointing, entropy_from_logits, gather, gather_object, get_config_model_id, get_peft_model, identity, inspect, is_conversational, is_peft_available, is_peft_model, is_rich_available, logger, math, nanmax, nanmin, nanstd, nn, np, pad, pd, peft, prepare_deepspeed, prepare_fsdp, prepare_multimodal_messages, print_prompt_completions_sample, profiling_context, profiling_decorator, selective_log_softmax, set_seed, shuffle_sequence_dict, shutdown_event_loop_in_daemon, split_pixel_values_by_grid, split_tensor_dict, start_event_loop_in_daemon, textwrap, time, torch, transformers, unsplit_pixel_values_by_grid, unwrap_model_for_generation, use_adapter, AutoModelForSequenceClassification, AutoProcessor, AutoTokenizer, Dataset, DistributedBackend, GenerationConfig, IterableDataset, LoraConfig, PeftConfig, PeftModel, PreTrainedModel, PreTrainedTokenizerBase, ProcessorMixin, RLOOConfig, RLOOTrainer, RewardFunc, SyncRefModelCallback, TrainerCallback, VLLMGeneration, Version, atexit, copy, create_model_from_path, defaultdict, deque, disable_dropout_in_model, gather, get_config_model_id, get_peft_model, identity, inspect, is_peft_available, is_peft_model, logger, nn, np, pad, pd, peft, prepare_deepspeed, prepare_fsdp, set_seed, shutdown_event_loop_in_daemon, start_event_loop_in_daemon, time, torch, transformers, Any, np, profiling_decorator, shuffle_sequence_dict, split_pixel_values_by_grid, split_tensor_dict, torch, unsplit_pixel_values_by_grid, PeftModel, PreTrainedModel, is_peft_available, logger, peft, torch)


import os
import math
import logging
from typing import *
from dataclasses import dataclass, field
from packaging.version import Version
import torch
import numpy as np
from contextlib import nullcontext
from torch.nn import functional as F
import inspect
from transformers import DataCollatorForSeq2Seq, DataCollatorForLanguageModeling as TransformersDataCollatorForLanguageModeling
from transformers.training_args import ParallelMode
from unsloth_zoo.device_type import DEVICE_TYPE, device_synchronize

# Wrap trainer with padding to right and enable training mode
import functools
from types import MethodType
try:
    from unsloth_zoo.gradient_checkpointing import reset_unsloth_gradient_checkpointing_buffers
except:
    def reset_unsloth_gradient_checkpointing_buffers(): pass
# Canonical reset lives in unsloth.models._utils so the SFT auto-packing wrapper and the plain
# Trainer loop can import the same helper; fall back to a no-op only if it can't be imported.
try:
    from unsloth.models._utils import _unsloth_reset_stray_compile_cache
except Exception:
    def _unsloth_reset_stray_compile_cache(self): pass
def prepare_for_training_mode(f):
    @functools.wraps(f)
    def wrapper(self, *args, **kwargs):
        # Drop any torch.compile graph cache poisoned by a stray pre-train forward.
        try:
            _unsloth_reset_stray_compile_cache(self)
        except Exception:
            pass
        # Finish the previous W&B run if this is a subsequent train() call.
        # We do this at the START of train() (not the end) so that
        # evaluate() / log() still work after train() completes.
        # HF's WandbCallback.setup() will call wandb.init() for the new run.
        # See: https://github.com/unslothai/unsloth/issues/3954
        if getattr(self, '_unsloth_training_completed', False):
            try:
                import wandb
                if wandb.run is not None:
                    wandb.finish()
                    # Reset HF's WandbCallback so it calls wandb.init() for the new run
                    for cb in self.callback_handler.callbacks:
                        if type(cb).__name__ == 'WandbCallback':
                            cb._initialized = False
                            break
            except:
                pass
        # Enable training mode
        _was_training = None
        # Get gradient checkpointing setting from training arguments
        use_gc = getattr(self.args, 'gradient_checkpointing', True)
        if hasattr(self, 'model') and hasattr(self.model, "training"):
            _was_training = self.model.training
        if hasattr(self, 'model') and hasattr(self.model, "for_training"):
            self.model.for_training(use_gradient_checkpointing=use_gc)
        output = f(self, *args, **kwargs)
        # Restore previous mode when possible
        if hasattr(self, 'model') and hasattr(self.model, "for_inference"):
            if _was_training is False:
                self.model.for_inference()
            elif _was_training is True and hasattr(self.model, "for_training"):
                self.model.for_training(use_gradient_checkpointing=use_gc)
        # Reset gradient checkpointing buffers to free memory while staying ready for next run
        try:
            reset_unsloth_gradient_checkpointing_buffers()
        except:
            pass
        # Mark that training completed so the next train() call can
        # finish this W&B run before starting a new one
        self._unsloth_training_completed = True
        return output
    return wrapper
pass

torch_compile_options = {
    "epilogue_fusion"   : True,
    "max_autotune"      : False,
    "shape_padding"     : True,
    "trace.enabled"     : False,
    "triton.cudagraphs" : False,
}

@torch.compile(dynamic = True, fullgraph = True, options = torch_compile_options,)
def chunked_hidden_states_selective_log_softmax(
    hidden_states: torch.Tensor,
    lm_head: torch.Tensor,
    index: torch.Tensor,
    chunks: int = 4,
    logit_scale_multiply: float = 0.0,
    logit_scale_divide: float = 0.0,
    logit_softcapping: float = 0.0,
    temperature: float = 1.0,
) -> torch.Tensor:
    # All Unsloth Zoo code licensed under AGPL3
    flat_hidden_states = hidden_states.reshape(-1, hidden_states.shape[-1])
    flat_index = index.reshape(-1)

    chunked_hidden_states = torch.chunk(flat_hidden_states, chunks=chunks, dim=0)
    chunked_index = torch.chunk(flat_index, chunks=chunks, dim=0)

    all_per_token_logps = []

    for chunk_hidden_states, chunk_index in zip(chunked_hidden_states, chunked_index):
        chunk_logits = chunk_hidden_states.to(lm_head.dtype) @ lm_head.t()

        if logit_scale_multiply != 0.0:
            chunk_logits = chunk_logits * logit_scale_multiply
        if logit_scale_divide != 0.0:
            chunk_logits = chunk_logits / logit_scale_divide
        if logit_softcapping != 0.0:
            chunk_logits = logit_softcapping * torch.tanh(chunk_logits / logit_softcapping)

        chunk_logits = chunk_logits.to(torch.float32)

        if temperature != 1.0:
            chunk_logits = chunk_logits / temperature

        selected_logits = torch.gather(chunk_logits, dim=-1, index=chunk_index.unsqueeze(-1)).squeeze(-1)
        logsumexp_values = torch.logsumexp(chunk_logits, dim=-1)
        per_token_logps = selected_logits - logsumexp_values
        all_per_token_logps.append(per_token_logps)

    all_per_token_logps = torch.concat(all_per_token_logps)

    all_per_token_logps = all_per_token_logps.reshape((hidden_states.shape[0], hidden_states.shape[1]))
    return all_per_token_logps

@torch.compile(dynamic = True, fullgraph = True, options = torch_compile_options,)
def chunked_selective_log_softmax(
    logits,
    index,
    temperature: float = 1.0,
    chunks: int = 4,
):
    chunked_logits = torch.chunk(logits.reshape(-1, logits.shape[-1]), chunks = chunks, dim = 0)
    chunked_index  = torch.chunk(index.reshape(-1), chunks = chunks, dim = 0)
    all_per_token_logps = []
    # Per-chunk selective_log_softmax.
    for chunk_logits, chunk_index in zip(chunked_logits, chunked_index):
        chunk_logits = chunk_logits.to(torch.float32)
        if temperature != 1.0:
            chunk_logits = chunk_logits / temperature
        selected_logits = torch.gather(chunk_logits, dim = -1, index = chunk_index.unsqueeze(-1)).squeeze(-1)
        logsumexp_values = torch.logsumexp(chunk_logits, dim = -1)
        per_token_logps = selected_logits - logsumexp_values
        all_per_token_logps.append(per_token_logps)
    pass
    all_per_token_logps = torch.concat(all_per_token_logps)
    all_per_token_logps = all_per_token_logps.reshape((logits.shape[0], logits.shape[1]))
    return all_per_token_logps

def calculate_pad_tokens_in_prompt(
    input_ids: torch.Tensor,
    logits_to_keep: int,
    pad_token_id: int
) -> torch.Tensor:
    """Count left-padded tokens per sequence, e.g. [pad, pad, pad, cat] -> 3."""
    if logits_to_keep >= input_ids.shape[1]:
        raise ValueError("logits_to_keep must be smaller than the sequence length.")

    prompt_section = input_ids[:, :-logits_to_keep]

    padding_mask = (prompt_section == pad_token_id)

    pad_token_counts = padding_mask.sum(dim=1)

    return pad_token_counts

def create_completion_attention_mask(
    completion_input_ids: torch.Tensor,
    left_pad_tokens_per_prompt: torch.Tensor,
    max_left_pad: int,
    pad_token_id: int
) -> torch.Tensor:
    """Build a completion mask that zeros leading prompt and trailing pad tokens.

    For [p,p,p,c,c,c,pad,pad,pad] (p=sliced prompt, c=completion, pad=padding)
    this returns [0,0,0,1,1,1,0,0,0].
    """
    batch_size, completion_len = completion_input_ids.shape
    device = completion_input_ids.device

    num_tokens_to_mask = max_left_pad - left_pad_tokens_per_prompt

    indices = torch.arange(completion_len, device=device).unsqueeze(0)
    shift_mask = indices >= num_tokens_to_mask.unsqueeze(1)

    non_padding_mask = (completion_input_ids != pad_token_id)

    final_mask = shift_mask & non_padding_mask

    return final_mask

def left_pack_padding(tensor: torch.Tensor, pad_id: int) -> torch.Tensor:
    """Move all padding tokens in each sequence to the right."""
    mask = (tensor != pad_id)
    # stable=True since the binary mask is unordered.
    sorted_indices = torch.argsort(mask, dim=1, descending=True, stable=True)
    packed_tensor = torch.gather(tensor, 1, sorted_indices)
    return packed_tensor

def align_logprobs_with_mask(
    logprob_tensor: torch.Tensor,
    attention_mask: torch.Tensor,
    pad_value: float = 0.0
) -> torch.Tensor:
    """Align a log probability tensor with a given attention mask."""

    device = logprob_tensor.device
    batch_size, logprob_seq_len = logprob_tensor.shape
    mask_seq_len = attention_mask.shape[1]

    padded_logprobs = torch.full(
        attention_mask.shape,
        fill_value=pad_value,
        dtype=logprob_tensor.dtype,
        device=device
    )

    left_pad_counts = torch.argmax(attention_mask, dim=1)

    cols = torch.arange(logprob_seq_len, device=device)
    dest_indices = left_pad_counts.unsqueeze(1) + cols

    # Destination row indices, shape [batch_size, logprob_seq_len].
    row_indices = torch.arange(batch_size, device=device).unsqueeze(1).expand_as(dest_indices)

    # Keep only in-bounds destinations, then scatter via advanced indexing.
    valid_mask = dest_indices < mask_seq_len
    valid_rows = row_indices[valid_mask]
    valid_cols = dest_indices[valid_mask]
    valid_vals = logprob_tensor[valid_mask]
    padded_logprobs[valid_rows, valid_cols] = valid_vals

    return padded_logprobs

def align_completion_tool_mask(
    tool_mask: torch.Tensor,
    completion_mask: torch.Tensor,
) -> torch.Tensor:
    """Align a raw completion-length tool/env mask with Unsloth's repacked loss mask."""
    if tool_mask is None:
        return completion_mask
    if tool_mask.shape[0] != completion_mask.shape[0]:
        raise ValueError("tool_mask batch size must match completion_mask batch size.")

    tool_mask = tool_mask.to(device=completion_mask.device)
    if tool_mask.shape == completion_mask.shape:
        aligned_tool_mask = tool_mask
    else:
        aligned_tool_mask = align_logprobs_with_mask(
            tool_mask,
            completion_mask,
            pad_value=0,
        )
    return completion_mask * aligned_tool_mask.to(dtype=completion_mask.dtype)

def autotune_batch_and_chunks(
    total_input_rows,
    seq_len,
    hidden_size,
    vocab_size,
    dtype_bytes=16,
    multiplier=None
):
    if multiplier is None:
        final_m = max(4, seq_len // 4096)
    else:
        final_m = multiplier

    if torch.cuda.is_available():
        free_bytes, _ = torch.cuda.mem_get_info()
        limit_gb = (free_bytes / (1024**3))*.80
    elif hasattr(torch, "xpu") and torch.xpu.is_available():
        # XPU: estimate free memory as total - reserved.
        total_mem = torch.xpu.get_device_properties(0).total_memory
        reserved_mem = torch.xpu.memory_reserved()
        free_bytes = total_mem - reserved_mem
        limit_gb = (free_bytes / (1024**3)) * 0.80
    else:
        # Fallback: assume 8GB available.
        limit_gb = 8.0

    bytes_to_gb = 1024**3

    b_vals = torch.arange(total_input_rows, 0, -1, device='cpu', dtype=torch.float32)

    hidden_gb = (b_vals * seq_len * hidden_size * dtype_bytes) / bytes_to_gb

    base_logits = ((b_vals/total_input_rows) * b_vals * seq_len * vocab_size * dtype_bytes) / bytes_to_gb
    logits_gb = base_logits / final_m

    total_mem_gb = hidden_gb + logits_gb

    valid_mask = total_mem_gb <= limit_gb
    valid_indices = torch.nonzero(valid_mask, as_tuple=False)

    if valid_indices.shape[0] == 0:
        #This means your GPU will OOM
        return 4, final_m

    best_idx = valid_indices[0].item()
    final_b = int(b_vals[best_idx].item())

    return final_b, final_m

def sanitize_logprob(logprob):
    """Local port of trl.scripts.vllm_serve.sanitize_logprob.
    Filters NaN logprobs from vLLM outputs."""
    value = logprob.logprob
    if math.isnan(value):
        logging.getLogger(__name__).warning(
            f"Generated NaN logprob, token logprob '{logprob}' will be ignored"
        )
        return None
    return value
@dataclass
class UnslothRLOOConfig(RLOOConfig):
    """
    
    Configuration class for the [`RLOOTrainer`].

    This class includes only the parameters that are specific to RLOO training. For a full list of training arguments,
    please refer to the [`~transformers.TrainingArguments`] documentation. Note that default values in this class may
    differ from those in [`~transformers.TrainingArguments`].

    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:
        > Parameters that control the model and reference model

        model_init_kwargs (`str`, `dict[str, Any]`, *optional*):
            Keyword arguments for [`~transformers.AutoModelForCausalLM.from_pretrained`], used when the `model`
            argument of the [`RLOOTrainer`] is provided as a string.
        trust_remote_code (`bool`, *optional*, defaults to `False`):
            Whether to allow loading models and tokenizers that ship custom Python code from the Hub. Forwarded to
            [`~transformers.AutoModelForCausalLM.from_pretrained`] and
            [`~transformers.AutoProcessor.from_pretrained`]. Also applied to reward-model and reward-tokenizer loads.
        router_aux_loss_coef (`float`, *optional*, defaults to `0.001`):
            Coefficient of the load-balancing auxiliary loss. Only has an effect when training a Mixture-of-Experts
            (MoE) model; for other models it does nothing. The auxiliary loss is added to the training loss with this
            weight. Set to `0.0` to disable it.
        disable_dropout (`bool`, *optional*, defaults to `False`):
            Whether to disable dropout in the model. This is useful for training with a reference model, as it prevents
            the model from generating different logprobs for the same input.

        > Parameters that control the data preprocessing

        remove_unused_columns (`bool`, *optional*, defaults to `False`):
            Whether to only keep the column `"prompt"` in the dataset. If you use a custom reward function that
            requires any column other than `"prompts"` and `"completions"`, you should keep this to `False`.
        num_generations (`int`, *optional*, defaults to `2`):
            Number of generations per prompt to sample. The effective batch size (num_processes * per_device_batch_size
            * gradient_accumulation_steps) must be evenly divisible by this value.
        num_generations_eval (`int` or `None`, *optional*):
            Number of generations to sample during evaluation. This allows using fewer generations during evaluation to
            save computation. If `None`, uses the value of `num_generations`.
        max_completion_length (`int` or `None`, *optional*, defaults to `256`):
            Maximum length of the generated completion.
        ds3_gather_for_generation (`bool`, *optional*, defaults to `True`):
            This setting applies to DeepSpeed ZeRO-3. If enabled, the policy model weights are gathered for generation,
            improving generation speed. However, disabling this option allows training models that exceed the VRAM
            capacity of a single GPU, albeit at the cost of slower generation. Disabling this option is not compatible
            with vLLM generation.
        shuffle_dataset (`bool`, *optional*, defaults to `True`):
            Whether to shuffle the training dataset.
        pad_to_multiple_of (`int`, *optional*):
            If set, the prompts ids and completions ids will be padded to a multiple of this value.

        > Parameters that control generation

        generation_batch_size (`int`, *optional*):
            Batch size to use for generation. If `None`, it defaults to the effective training batch size:
            `per_device_train_batch_size * num_processes * steps_per_generation`. In other words, there is one
            generation batch processed per optimization step. Mutually exclusive with `steps_per_generation`.
        steps_per_generation (`int`, *optional*):
            Number of steps per generation. If `None`, it defaults to `gradient_accumulation_steps`. Mutually exclusive
            with `generation_batch_size`.
        temperature (`float`, defaults to `1.0`):
            Temperature for sampling. The higher the temperature, the more random the completions.
        top_p (`float`, *optional*, defaults to `1.0`):
            Float that controls the cumulative probability of the top tokens to consider. Must be in (0, 1]. Set to
            `1.0` to consider all tokens.
        top_k (`int`, *optional*, defaults to `0`):
            Number of highest probability vocabulary tokens to keep for top-k-filtering. If `0`, top-k-filtering is
            disabled and all tokens are considered.
        min_p (`float`, *optional*):
            Minimum token probability, which will be scaled by the probability of the most likely token. It must be a
            value between `0.0` and `1.0`. Typical values are in the `0.01-0.2` range.
        generation_kwargs (`dict[str, Any]`, *optional*):
            Additional keyword arguments to pass to [`~transformers.GenerationConfig`] (if using transformers) or
            `SamplingParams` (if using vLLM) when sampling completions. This can be used to further customize the
            generation behavior, such as setting `suppress_tokens`, `num_beams`, etc. If it contains keys that conflict
            with the other generation parameters (like `min_p`, `top_p`, etc.), they will override them.
        chat_template_kwargs (`dict[str, Any]`, *optional*):
            Additional keyword arguments to pass to the `apply_chat_template` function when generating completions.
        repetition_penalty (`float`, *optional*, defaults to `1.0`):
            Float that penalizes new tokens based on whether they appear in the prompt and the generated text so far.
            Values > `1.0` encourage the model to use new tokens, while values < `1.0` encourage the model to repeat
            tokens.
        cache_implementation (`str`, *optional*):
            Implementation of the cache method for faster generation when `use_vllm` is set to `False`.

        > Parameters that control generation acceleration powered by vLLM

        use_vllm (`bool`, *optional*, defaults to `False`):
            Whether to use vLLM for generating completions. If set to `True`, the trainer will use vLLM for generation
            instead of the default model.generate(). Requires `vllm` to be installed.
        vllm_mode (`str`, *optional*, defaults to `"colocate"`):
            Mode to use for vLLM integration when `use_vllm` is set to `True`. Must be one of `"server"` or
            `"colocate"`.

            - `"server"`: The trainer will send generation requests to a separate vLLM server. Make sure a TRL vLLM
              server is running (start with `trl vllm-serve`).
            - `"colocate"`: vLLM will run in the same process and share the training GPUs. This avoids the need for a
              separate server but may cause resource contention with training.
        vllm_model_impl (`str`, *optional*, defaults to `"vllm"`):
            Model implementation to use for vLLM. Must be one of `"transformers"` or `"vllm"`. `"transformers"`: Use
            the `transformers` backend for model implementation. `"vllm"`: Use the `vllm` library for model
            implementation.
        vllm_structured_outputs_regex (`str`, *optional*):
            Regex for vLLM structured outputs. If `None` (default), structured outputs is disabled.

        > Parameters that control the vLLM server (only used when `vllm_mode` is `"server"`)

        vllm_server_base_url (`str`, *optional*):
            Base URL for the vLLM server (e.g., `"http://localhost:8000"`). If provided, `vllm_server_host` and
            `vllm_server_port` are ignored.
        vllm_server_host (`str`, *optional*, defaults to `"0.0.0.0"`):
            Host of the vLLM server to connect to. Ignored if `vllm_server_base_url` is provided.
        vllm_server_port (`int`, *optional*, defaults to `8000`):
            Port of the vLLM server to connect to. Ignored if `vllm_server_base_url` is provided.
        vllm_server_timeout (`float`, *optional*, defaults to `240.0`):
            Total timeout duration in seconds to wait for the vLLM server to be up. If the server is not up after the
            timeout, a `ConnectionError` is raised.
        vllm_group_port (`int`, *optional*, defaults to `51216`):
            Port number for the weight update group. This is used to communicate with the vLLM server. Unless the port
            is occupied, there is no need to change it.

        > Parameters that control colocated vLLM execution (only used when `vllm_mode` is `"colocate"`)

        vllm_gpu_memory_utilization (`float`, *optional*, defaults to `0.3`):
            Control the GPU memory utilization for vLLM. This setting only applies when `vllm_mode` is set to
            `"colocate"`. If you are using `vllm_mode="server"`, this parameter must be passed separately when
            launching the vLLM server via the `--vllm_gpu_memory_utilization` flag.
        vllm_max_model_length (`int`, *optional*):
            Context window for vLLM. Set it to at least the maximum prompt length in the dataset plus
            `max_completion_length`; if omitted, it is inferred from the model config.
        vllm_tensor_parallel_size (`int`, *optional*, defaults to `1`):
            Control the tensor parallel size for vLLM. This setting only applies when `vllm_mode` is set to
            `"colocate"`. If you are using `vllm_mode="server"`, this parameter must be passed separately when
            launching the vLLM server via the `--vllm_tensor_parallel_size` flag.
        vllm_enable_sleep_mode (`bool`, *optional*, defaults to `False`):
            Enable vLLM sleep mode to offload weights/cache during the optimizer step. Keeps GPU memory usage low, but
            waking the engine adds host–device transfer latency.

        > Parameters that control generation acceleration powered by transformers continuous batching

        use_transformers_continuous_batching (`bool`, *optional*, defaults to `False`):
            Whether to use transformers' continuous batching engine for generating completions. Requires
            `transformers>=5.8.0`.
        transformers_continuous_batching_config (`dict`, *optional*):
            Keyword arguments for [`~transformers.generation.ContinuousBatchingConfig`].

        > Parameters that control the training

        beta (`float`, *optional*, defaults to `0.05`):
            KL coefficient. If `0.0`, the reference model is not loaded, reducing memory usage and improving training
            speed.
        num_iterations (`int`, *optional*, defaults to `1`):
            Number of iterations per batch (denoted as μ in the algorithm).
        epsilon (`float`, *optional*, defaults to `0.2`):
            Epsilon value for clipping.
        epsilon_high (`float`, *optional*):
            Upper-bound epsilon value for clipping. If not specified, it defaults to the same value as the lower-bound
            specified in argument `epsilon`. Paper [DAPO](https://huggingface.co/papers/2503.14476) recommends `0.28`.
        reward_weights (`list[float]`, *optional*):
            Weights for each reward function. Must match the number of reward functions. If `None`, all rewards are
            weighted equally with weight `1.0`.
        normalize_advantages (`bool`, *optional*, defaults to `False`):
            Whether to normalize advantages. Normalization is done per generation batch to have mean `0.0` and standard
            deviation of `1.0`.
        reward_clip_range (`tuple[float, float]`, *optional*):
            Clip range for rewards as (min, max). If `None`, no clipping is applied.
        mask_truncated_completions (`bool`, *optional*, defaults to `False`):
            When enabled, truncated completions are excluded from the loss calculation, preventing them from being
            incorrectly penalized and introducing noise during training. According to the
            [DAPO](https://huggingface.co/papers/2503.14476) paper, this is a good practice for training stability.
        sync_ref_model (`bool`, *optional*, defaults to `False`):
            Whether to synchronize the reference model with the active model every `ref_model_sync_steps` steps, using
            the `ref_model_mixup_alpha` parameter. This synchronization originates from the
            [TR-DPO](https://huggingface.co/papers/2404.09656) paper.
        ref_model_mixup_alpha (`float`, *optional*, defaults to `0.6`):
            α parameter from the [TR-DPO](https://huggingface.co/papers/2404.09656) paper, which controls the mix
            between the current policy and the previous reference policy during updates. The reference policy is
            updated according to the equation: `π_ref = α * π_θ + (1 - α) * π_ref_prev`. To use this parameter, you
            must set `sync_ref_model=True`.
        ref_model_sync_steps (`int`, *optional*, defaults to `512`):
            τ parameter from the [TR-DPO](https://huggingface.co/papers/2404.09656) paper, which determines how
            frequently the current policy is synchronized with the reference policy. To use this parameter, you must
            set `sync_ref_model=True`.

        > Parameters that control the logging

        log_completions (`bool`, *optional*, defaults to `False`):
            Whether to log a sample of (prompt, completion) pairs every `logging_steps` steps. If `rich` is installed,
            it prints the sample. If `wandb` and/or `trackio` logging is enabled, it logs it to `wandb` and/or
            `trackio`.
        num_completions_to_print (`int`, *optional*):
            Number of completions to print with `rich`. If `None`, all completions are logged.
        log_unique_prompts (`bool`, *optional*, defaults to `False`):
            Whether to log unique prompts. If `True`, only unique prompts are logged. If `False`, all prompts are
            logged.

        > Deprecated parameters

        use_transformers_paged:

            <Deprecated version="1.2.0">

            Parameter `use_transformers_paged` is deprecated and will be removed in version v2.0.0. Use
            `use_transformers_continuous_batching` instead.

            </Deprecated>

    > [!NOTE]
    > These parameters have default values different from [`~transformers.TrainingArguments`]:
    > - `logging_steps`: Defaults to `10` instead of `500`.
    > - `gradient_checkpointing`: Defaults to `True` instead of `False`.
    > - `bf16`: Defaults to `True` if `fp16` is not set, instead of `False`.
    > - `learning_rate`: Defaults to `1e-6` instead of `5e-5`.
    
    """
    vllm_sampling_params: Optional[Any] = field(
        default = None,
        metadata = {'help': 'vLLM SamplingParams'},
    )
    unsloth_num_chunks : Optional[int] = field(
        default = -1,
        metadata = {'help': 'Chunk size to reduce memory usage. -1 is most efficient.'},
    )
    unsloth_logit_chunk_multiplier : Optional[int] = field(
            default = None,
            metadata = {'help': 'Multiplier for chunked logit computations.'},
        )
    unsloth_grpo_mini_batch : Optional[int] = field(
        default = None,
        metadata = {'help': 'Mini batch size for GRPO hidden state accumulation. Default is None unless user defines it.'},
    )
    
    def __init__(
        self,
        output_dir = None,
        per_device_train_batch_size = 4,
        num_train_epochs = 3.0,
        max_steps = -1,
        learning_rate = 5e-05,
        lr_scheduler_type = 'linear',
        lr_scheduler_kwargs = None,
        warmup_steps = 0.1,
        optim = 'adamw_8bit',
        optim_args = None,
        weight_decay = 0.001,
        adam_beta1 = 0.9,
        adam_beta2 = 0.999,
        adam_epsilon = 1e-08,
        optim_target_modules = None,
        gradient_accumulation_steps = 2,
        average_tokens_across_devices = True,
        max_grad_norm = 1.0,
        label_smoothing_factor = 0.0,
        bf16 = False,
        fp16 = False,
        bf16_full_eval = False,
        fp16_full_eval = False,
        tf32 = None,
        gradient_checkpointing = True,
        gradient_checkpointing_kwargs = None,
        torch_compile = False,
        torch_compile_backend = None,
        torch_compile_mode = None,
        use_liger_kernel = False,
        liger_kernel_config = None,
        use_cache = False,
        neftune_noise_alpha = None,
        torch_empty_cache_steps = 250,
        auto_find_batch_size = False,
        logging_strategy = 'steps',
        logging_steps = 1,
        logging_first_step = False,
        log_on_each_node = True,
        logging_nan_inf_filter = False,
        include_num_input_tokens_seen = False,
        log_level = 'passive',
        log_level_replica = 'warning',
        disable_tqdm = None,
        report_to = 'none',
        run_name = None,
        project = 'huggingface',
        trackio_space_id = 'trackio',
        eval_strategy = 'no',
        eval_steps = None,
        eval_delay = 0,
        per_device_eval_batch_size = 4,
        prediction_loss_only = False,
        eval_on_start = False,
        eval_do_concat_batches = True,
        eval_use_gather_object = False,
        eval_accumulation_steps = 2,
        batch_eval_metrics = False,
        save_only_model = False,
        save_strategy = 'steps',
        save_steps = 500,
        save_on_each_node = False,
        save_total_limit = None,
        enable_jit_checkpoint = False,
        push_to_hub = False,
        hub_token = None,
        hub_private_repo = None,
        hub_model_id = None,
        hub_strategy = 'every_save',
        hub_always_push = False,
        hub_revision = None,
        load_best_model_at_end = False,
        metric_for_best_model = None,
        greater_is_better = None,
        ignore_data_skip = False,
        restore_callback_states_from_checkpoint = False,
        full_determinism = False,
        seed = 3407,
        data_seed = 3407,
        use_cpu = False,
        accelerator_config = None,
        parallelism_config = None,
        dataloader_drop_last = False,
        dataloader_num_workers = 0,
        dataloader_pin_memory = True,
        dataloader_persistent_workers = False,
        dataloader_prefetch_factor = None,
        remove_unused_columns = False,
        label_names = None,
        train_sampling_strategy = 'random',
        length_column_name = 'length',
        ddp_find_unused_parameters = None,
        ddp_bucket_cap_mb = None,
        ddp_broadcast_buffers = None,
        ddp_backend = None,
        ddp_timeout = 1800,
        fsdp = None,
        fsdp_config = None,
        deepspeed = None,
        debug = '',
        skip_memory_metrics = True,
        do_train = False,
        do_eval = False,
        do_predict = False,
        resume_from_checkpoint = None,
        warmup_ratio = None,
        logging_dir = None,
        local_rank = -1,
        model_init_kwargs = None,
        trust_remote_code = False,
        router_aux_loss_coef = 0.001,
        disable_dropout = False,
        num_generations = 8,
        num_generations_eval = None,
        max_completion_length = 256,
        ds3_gather_for_generation = True,
        shuffle_dataset = True,
        pad_to_multiple_of = None,
        generation_batch_size = None,
        steps_per_generation = None,
        temperature = 1.0,
        top_p = 1.0,
        top_k = None,
        min_p = None,
        generation_kwargs = {},
        chat_template_kwargs = None,
        repetition_penalty = 1.0,
        cache_implementation = None,
        use_vllm = False,
        vllm_mode = 'colocate',
        vllm_model_impl = 'vllm',
        vllm_enable_sleep_mode = False,
        vllm_structured_outputs_regex = None,
        vllm_server_base_url = None,
        vllm_server_host = '0.0.0.0',
        vllm_server_port = 8000,
        vllm_server_timeout = 240.0,
        vllm_group_port = 51216,
        vllm_gpu_memory_utilization = 0.3,
        vllm_max_model_length = None,
        vllm_tensor_parallel_size = 1,
        beta = 0.05,
        num_iterations = 1,
        epsilon = 0.2,
        epsilon_high = None,
        reward_weights = None,
        normalize_advantages = False,
        reward_clip_range = None,
        mask_truncated_completions = False,
        sync_ref_model = False,
        ref_model_mixup_alpha = 0.6,
        ref_model_sync_steps = 512,
        log_completions = False,
        num_completions_to_print = None,
        log_unique_prompts = False,
        use_transformers_continuous_batching = False,
        transformers_continuous_batching_config = None,
        use_transformers_paged = False,
        vllm_sampling_params = None,
        unsloth_num_chunks = -1,
        unsloth_logit_chunk_multiplier = None,
        unsloth_grpo_mini_batch = None,
        
        **kwargs,
    ):
        if learning_rate < 1e-7: print(f'Unsloth: Your learning rate of `{learning_rate}` is too small and less than 1e-7! Consider increasing it, otherwise gradient updates will be close to 0!')
        if learning_rate > 1: print(f'Unsloth: Your learning rate of `{learning_rate}` is way too larger > 1! Consider decreasing it to 1e-1, otherwise gradient updates will explode!')
        if num_train_epochs is None:
            num_train_epochs = 3.0  # Default to 3 epochs if None, max_steps will override
        if output_dir is None and save_strategy == 'steps' and save_steps == 500:
            output_dir = 'unsloth_training_checkpoints'
            save_strategy = 'no'
        if os.environ.get('UNSLOTH_ENABLE_FLEX_ATTENTION', '0') == '1':
            from unsloth_zoo.flex_attention import HAS_FLEX_ATTENTION
            if HAS_FLEX_ATTENTION and pad_to_multiple_of is None:
                from unsloth_zoo.flex_attention import FLEX_ATTENTION_BLOCK_SIZE
                pad_to_multiple_of = FLEX_ATTENTION_BLOCK_SIZE
        
        if steps_per_generation is None and generation_batch_size is None:
            ga = gradient_accumulation_steps
            world_size = int(os.environ.get('WORLD_SIZE', '1'))
            if (ga * world_size * per_device_train_batch_size) % num_generations != 0:
                print('Unsloth: We now expect `per_device_train_batch_size` * `gradient_accumulation_steps` * `world_size` to be a multiple of `num_generations`.\nWe will change the batch size of ' + str(per_device_train_batch_size) + ' to the `num_generations` of ' + str(num_generations))
                per_device_train_batch_size = num_generations
        
        if temperature <= 0:
            raise ValueError('Unsloth: Please set a positive non-zero temperature since your results will be wrong.')
        elif temperature >= 10:
            raise ValueError('Unsloth: Please set a positive non-zero temperature less than 10, since sampling will be quite erratic.')
        
        
        super().__init__(
            output_dir = output_dir,
            per_device_train_batch_size = per_device_train_batch_size,
            num_train_epochs = num_train_epochs,
            max_steps = max_steps,
            learning_rate = learning_rate,
            lr_scheduler_type = lr_scheduler_type,
            lr_scheduler_kwargs = lr_scheduler_kwargs,
            warmup_steps = warmup_steps,
            optim = optim,
            optim_args = optim_args,
            weight_decay = weight_decay,
            adam_beta1 = adam_beta1,
            adam_beta2 = adam_beta2,
            adam_epsilon = adam_epsilon,
            optim_target_modules = optim_target_modules,
            gradient_accumulation_steps = gradient_accumulation_steps,
            average_tokens_across_devices = average_tokens_across_devices,
            max_grad_norm = max_grad_norm,
            label_smoothing_factor = label_smoothing_factor,
            bf16 = bf16,
            fp16 = fp16,
            bf16_full_eval = bf16_full_eval,
            fp16_full_eval = fp16_full_eval,
            tf32 = tf32,
            gradient_checkpointing = gradient_checkpointing,
            gradient_checkpointing_kwargs = gradient_checkpointing_kwargs,
            torch_compile = torch_compile,
            torch_compile_backend = torch_compile_backend,
            torch_compile_mode = torch_compile_mode,
            use_liger_kernel = use_liger_kernel,
            liger_kernel_config = liger_kernel_config,
            use_cache = use_cache,
            neftune_noise_alpha = neftune_noise_alpha,
            torch_empty_cache_steps = torch_empty_cache_steps,
            auto_find_batch_size = auto_find_batch_size,
            logging_strategy = logging_strategy,
            logging_steps = logging_steps,
            logging_first_step = logging_first_step,
            log_on_each_node = log_on_each_node,
            logging_nan_inf_filter = logging_nan_inf_filter,
            include_num_input_tokens_seen = include_num_input_tokens_seen,
            log_level = log_level,
            log_level_replica = log_level_replica,
            disable_tqdm = disable_tqdm,
            report_to = report_to,
            run_name = run_name,
            project = project,
            trackio_space_id = trackio_space_id,
            eval_strategy = eval_strategy,
            eval_steps = eval_steps,
            eval_delay = eval_delay,
            per_device_eval_batch_size = per_device_eval_batch_size,
            prediction_loss_only = prediction_loss_only,
            eval_on_start = eval_on_start,
            eval_do_concat_batches = eval_do_concat_batches,
            eval_use_gather_object = eval_use_gather_object,
            eval_accumulation_steps = eval_accumulation_steps,
            batch_eval_metrics = batch_eval_metrics,
            save_only_model = save_only_model,
            save_strategy = save_strategy,
            save_steps = save_steps,
            save_on_each_node = save_on_each_node,
            save_total_limit = save_total_limit,
            enable_jit_checkpoint = enable_jit_checkpoint,
            push_to_hub = push_to_hub,
            hub_token = hub_token,
            hub_private_repo = hub_private_repo,
            hub_model_id = hub_model_id,
            hub_strategy = hub_strategy,
            hub_always_push = hub_always_push,
            hub_revision = hub_revision,
            load_best_model_at_end = load_best_model_at_end,
            metric_for_best_model = metric_for_best_model,
            greater_is_better = greater_is_better,
            ignore_data_skip = ignore_data_skip,
            restore_callback_states_from_checkpoint = restore_callback_states_from_checkpoint,
            full_determinism = full_determinism,
            seed = seed,
            data_seed = data_seed,
            use_cpu = use_cpu,
            accelerator_config = accelerator_config,
            parallelism_config = parallelism_config,
            dataloader_drop_last = dataloader_drop_last,
            dataloader_num_workers = dataloader_num_workers,
            dataloader_pin_memory = dataloader_pin_memory,
            dataloader_persistent_workers = dataloader_persistent_workers,
            dataloader_prefetch_factor = dataloader_prefetch_factor,
            remove_unused_columns = remove_unused_columns,
            label_names = label_names,
            train_sampling_strategy = train_sampling_strategy,
            length_column_name = length_column_name,
            ddp_find_unused_parameters = ddp_find_unused_parameters,
            ddp_bucket_cap_mb = ddp_bucket_cap_mb,
            ddp_broadcast_buffers = ddp_broadcast_buffers,
            ddp_backend = ddp_backend,
            ddp_timeout = ddp_timeout,
            fsdp = fsdp,
            fsdp_config = fsdp_config,
            deepspeed = deepspeed,
            debug = debug,
            skip_memory_metrics = skip_memory_metrics,
            do_train = do_train,
            do_eval = do_eval,
            do_predict = do_predict,
            resume_from_checkpoint = resume_from_checkpoint,
            warmup_ratio = warmup_ratio,
            logging_dir = logging_dir,
            local_rank = local_rank,
            model_init_kwargs = model_init_kwargs,
            trust_remote_code = trust_remote_code,
            router_aux_loss_coef = router_aux_loss_coef,
            disable_dropout = disable_dropout,
            num_generations = num_generations,
            num_generations_eval = num_generations_eval,
            max_completion_length = max_completion_length,
            ds3_gather_for_generation = ds3_gather_for_generation,
            shuffle_dataset = shuffle_dataset,
            pad_to_multiple_of = pad_to_multiple_of,
            generation_batch_size = generation_batch_size,
            steps_per_generation = steps_per_generation,
            temperature = temperature,
            top_p = top_p,
            top_k = top_k,
            min_p = min_p,
            generation_kwargs = generation_kwargs,
            chat_template_kwargs = chat_template_kwargs,
            repetition_penalty = repetition_penalty,
            cache_implementation = cache_implementation,
            use_vllm = use_vllm,
            vllm_mode = vllm_mode,
            vllm_model_impl = vllm_model_impl,
            vllm_enable_sleep_mode = vllm_enable_sleep_mode,
            vllm_structured_outputs_regex = vllm_structured_outputs_regex,
            vllm_server_base_url = vllm_server_base_url,
            vllm_server_host = vllm_server_host,
            vllm_server_port = vllm_server_port,
            vllm_server_timeout = vllm_server_timeout,
            vllm_group_port = vllm_group_port,
            vllm_gpu_memory_utilization = vllm_gpu_memory_utilization,
            vllm_max_model_length = vllm_max_model_length,
            vllm_tensor_parallel_size = vllm_tensor_parallel_size,
            beta = beta,
            num_iterations = num_iterations,
            epsilon = epsilon,
            epsilon_high = epsilon_high,
            reward_weights = reward_weights,
            normalize_advantages = normalize_advantages,
            reward_clip_range = reward_clip_range,
            mask_truncated_completions = mask_truncated_completions,
            sync_ref_model = sync_ref_model,
            ref_model_mixup_alpha = ref_model_mixup_alpha,
            ref_model_sync_steps = ref_model_sync_steps,
            log_completions = log_completions,
            num_completions_to_print = num_completions_to_print,
            log_unique_prompts = log_unique_prompts,
            use_transformers_continuous_batching = use_transformers_continuous_batching,
            transformers_continuous_batching_config = transformers_continuous_batching_config,
            use_transformers_paged = use_transformers_paged,**kwargs)
        self.vllm_sampling_params = vllm_sampling_params
        self.unsloth_num_chunks = unsloth_num_chunks
        if unsloth_grpo_mini_batch is not None:
            if self.generation_batch_size >= unsloth_grpo_mini_batch:
                self.unsloth_grpo_mini_batch = unsloth_grpo_mini_batch
            else:
                raise ValueError(
                    f"Unsloth GRPO mini batch size needs to be less than or equal to the effective generation batch size, "
                    f"which is self.per_device_train_batch_size * gradient_accumulation_steps."
                )
        self.unsloth_logit_chunk_multiplier = unsloth_logit_chunk_multiplier
        
        # Unsloth: Remove use_reentrant=False forced by TRL 0.27.0+
        if getattr(self, 'gradient_checkpointing_kwargs', None) is not None:
            if 'use_reentrant' in self.gradient_checkpointing_kwargs:
                del self.gradient_checkpointing_kwargs['use_reentrant']

pass

class _UnslothRLOOTrainer(_BaseTrainer):
    """"""

    _tag_names = ["trl", "rloo"]
    _name = "RLOO"
    _paper = {
        "title": "Back to Basics: Revisiting REINFORCE-Style Optimization for Learning from Human Feedback in LLMs",
        "id": "2402.14740",
        # docstyle-ignore
        "citation": textwrap.dedent("""\
            @inproceedings{ahmadian2024back,
                title        = {{Back to Basics: Revisiting REINFORCE-Style Optimization for Learning from Human Feedback in LLMs}},
                author       = {Arash Ahmadian and Chris Cremer and Matthias Gall{\'{e}} and Marzieh Fadaee and Julia Kreutzer and Olivier Pietquin and Ahmet {\"{U}}st{\"{u}}n and Sara Hooker},
                year         = 2024,
                booktitle    = {Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), {ACL} 2024, Bangkok, Thailand, August 11-16, 2024},
                pages        = {12248--12267},
                publisher    = {Association for Computational Linguistics},
                editor       = {Lun{-}Wei Ku and Andre Martins and Vivek Srikumar},
            }"""),
    }

    def __init__(
        self,
        model: "str | PreTrainedModel | PeftModel",
        reward_funcs: RewardFunc | list[RewardFunc],
        args: RLOOConfig | None = None,
        train_dataset: Dataset | IterableDataset | None = None,
        eval_dataset: Dataset | IterableDataset | dict[str, Dataset | IterableDataset] | None = None,
        processing_class: PreTrainedTokenizerBase | ProcessorMixin | None = None,
        reward_processing_classes: PreTrainedTokenizerBase | list[PreTrainedTokenizerBase] | None = None,
        callbacks: list[TrainerCallback] | None = None,
        optimizers: tuple[torch.optim.Optimizer | None, torch.optim.lr_scheduler.LambdaLR | None] = (None, None),
        peft_config: "PeftConfig | None" = None,
    ):

        if hasattr(model, 'vllm_engine') and hasattr(args, 'use_vllm'):
            if (getattr(args, 'use_vllm', False) == False):
                args.use_vllm = True
        # Args
        if args is None:
            model_name = model if isinstance(model, str) else get_config_model_id(model.config)
            model_name = model_name.split("/")[-1]
            args = RLOOConfig(f"{model_name}-RLOO")

        # Model
        if isinstance(model, str):
            model_init_kwargs = args.model_init_kwargs or {}
            # Distributed training requires device_map=None ["auto" fails]
            if args.distributed_state.distributed_type in ["MULTI_GPU", "DEEPSPEED"]:
                model_init_kwargs["device_map"] = None
            model_init_kwargs.setdefault("trust_remote_code", args.trust_remote_code)
            model = create_model_from_path(model, **model_init_kwargs)
        else:
            if args.model_init_kwargs is not None:
                logger.warning(
                    "You passed `model_init_kwargs` to the `RLOOConfig`, but your model is already instantiated. "
                    "The `model_init_kwargs` will be ignored."
                )
        # Non-quantized models do not have the `is_loaded_in_{8,4}bit` attributes, whereas quantized models do
        _is_quantized_model = getattr(model, "is_loaded_in_4bit", False) or getattr(model, "is_loaded_in_8bit", False)

        # Some models [SmolVLM/Idefics3] don't support `logits_to_keep` argument and error out if we pass it
        # Inspect the forward method before we wrap the model with PEFT
        self.model_kwarg_keys = (
            inspect.signature(model.forward).parameters.keys()
            if not hasattr(model, "get_base_model")
            else inspect.signature(model.get_base_model().forward).parameters.keys()
        )

        # Processing class
        if processing_class is None:
            processing_class = AutoProcessor.from_pretrained(
                get_config_model_id(model.config),
                truncation_side="left",
                padding_side="left",
                trust_remote_code=args.trust_remote_code,
            )

        if args.use_transformers_continuous_batching and isinstance(processing_class, ProcessorMixin):
            raise ValueError(
                "`use_transformers_continuous_batching` does not support multimodal models. Use `use_vllm` instead."
            )

        # Handle pad token for processors or tokenizers
        if isinstance(processing_class, ProcessorMixin):
            self._tokenizer = processing_class.tokenizer
        elif isinstance(processing_class, PreTrainedTokenizerBase):
            self._tokenizer = processing_class
        else:
            raise TypeError("The `processing_class` must be either a `PreTrainedTokenizerBase` or a `ProcessorMixin`")

        if self._tokenizer.pad_token is None:
            self._tokenizer.pad_token = self._tokenizer.eos_token

        # PEFT
        if False:
            if not is_peft_available():
                raise ImportError(
                    "You passed `peft_config` but the `peft` library is not installed. "
                    "Install it with `pip install trl[peft]`."
                )
            if not isinstance(peft_config, PeftConfig):
                raise TypeError(
                    f"`peft_config` must be a `peft.PeftConfig` instance (e.g. `peft.LoraConfig`), "
                    f"got {type(peft_config).__name__}."
                )
            if is_peft_model(model):
                raise ValueError(
                    "You passed a `PeftModel` instance together with a `peft_config` to the trainer. Please first merge "
                    "and unload the existing adapter, save the resulting base model, and then pass that base model along "
                    "with the new `peft_config` to the trainer."
                )
            # Create PEFT model
            # ZeRO-3 + PEFT for non-quantized models:
            # - PEFT's default autocast_adapter_dtype=True upcasts LoRA adapter params to fp32 even when the base model is bf16.
            # - ZeRO-3's _allgather_params_coalesced allocates output buffers using the dtype of the first persistent parameter,
            #   so mixed-dtype persistent_parameters [bf16 base + fp32 LoRA] cause a TypeError on the first optimizer step.
            # - Passing autocast_adapter_dtype=False keeps adapter params in the base model dtype [bf16], fixing the mismatch.
            # - This is safe: the fp32 upcast is a QLoRA-specific concern [low-bit quantized base models], not needed for
            #   non-quantized bf16 training.
            # - See:
            #   - TRL issue: https://github.com/huggingface/trl/issues/6089
            #   - Upstream issue: https://github.com/deepspeedai/DeepSpeed/issues/8072
            # - autocast_adapter_dtype was introduced in PEFT 0.12.0; before, no upcast existed: no need to pass the kwarg
            get_peft_model_kwargs = {}
            if (
                args.deepspeed_plugin is not None
                and args.deepspeed_plugin.zero_stage == 3
                and not _is_quantized_model
                and Version(peft.__version__) >= Version("0.12.0")
            ):
                get_peft_model_kwargs["autocast_adapter_dtype"] = False
            model = get_peft_model(model, peft_config, **get_peft_model_kwargs)

        elif is_peft_model(model):
            # If the model is a PEFT model with a pretrained adapter, we need to create a "ref" adapter that is a copy
            # of the "default" adapter, so that we can use it as the reference model during the training. PEFT only
            # supports one adapter per model when the LoRA config uses `target_parameters` [see peft#3340], so in that
            # case we skip the "ref" adapter and compute the reference log probs with adapters disabled, i.e. with the
            # base model.
            default_config = model.peft_config["default"]
            if isinstance(default_config, LoraConfig) and default_config.target_parameters:
                logger.warning(
                    "PEFT can't add a frozen reference adapter alongside one that uses `target_parameters` "
                    "(peft#3340], so the reference log probs are computed from the base model [adapters disabled]. "
                    "If you wrapped the model only to apply LoRA, pass a `peft_config` to the trainer instead; if you "
                    "wrapped it deliberately (pretrained adapter or custom init), note that the base model matches "
                    "your adapter only when it's freshly zero-initialized. If it is, this warning is safe to ignore."
                )
            else:
                model.add_adapter("ref", default_config)
                for name, param in model.named_parameters():
                    if ".default." in name:
                        ref_name = name.replace(".default.", ".ref.")
                        ref_param = model.get_parameter(ref_name)
                        ref_param.data.copy_(param.data)

        # When using gradient checkpointing with PEFT, we need to enable input gradients. transformers.Trainer normally
        # handles this, but a bug currently prevents it; see https://github.com/huggingface/transformers/issues/42489
        if is_peft_model(model) and args.gradient_checkpointing:
            model.enable_input_require_grads()

        # When using QLoRA, the PEFT adapter weights are converted to bf16 to follow the recommendations from the
        # original paper [see https://huggingface.co/papers/2305.14314, paragraph 3]. Normally, this can be done by
        # passing `autocast_adapter_dtype=False` to `get_peft_model`, but this option is not yet supported for
        # quantized models. See: https://github.com/huggingface/peft/issues/2889
        if _is_quantized_model:
            for param in model.parameters():
                if param.requires_grad:
                    param.data = param.data.to(torch.bfloat16)

        # Reward functions
        if not isinstance(reward_funcs, list):
            reward_funcs = [reward_funcs]
        self.reward_func_names = []
        for i, reward_func in enumerate(reward_funcs):
            if isinstance(reward_func, str):
                model_init_kwargs = args.model_init_kwargs or {}
                # Distributed training requires device_map=None ["auto" fails]
                if args.distributed_state.distributed_type in ["MULTI_GPU", "DEEPSPEED"]:
                    model_init_kwargs["device_map"] = None
                model_init_kwargs.setdefault("trust_remote_code", args.trust_remote_code)
                reward_funcs[i] = AutoModelForSequenceClassification.from_pretrained(
                    reward_func, num_labels=1, **model_init_kwargs
                )
            if isinstance(reward_funcs[i], nn.Module):  # Use Module over PretrainedModel for compat w/ compiled models
                self.reward_func_names.append(get_config_model_id(reward_funcs[i].config).split("/")[-1])
            else:
                self.reward_func_names.append(reward_funcs[i].__name__)
        self.reward_funcs = reward_funcs

        self._has_async_funcs = any(inspect.iscoroutinefunction(func) for func in self.reward_funcs)
        if self._has_async_funcs:
            self.async_loop_thread, self.async_loop, self.async_loop_ready_event = start_event_loop_in_daemon(
                name="RLOOTrainer-AsyncRewardLoop"
            )
            # wait until the event loop is running in the daemon thread
            self.async_loop_ready_event.wait()
            atexit.register(shutdown_event_loop_in_daemon, self.async_loop_thread, self.async_loop)

        # Reward weights
        if args.reward_weights is not None:
            if len(args.reward_weights) != len(reward_funcs):
                raise ValueError(
                    f"Number of reward weights ({len(args.reward_weights)}) must match number of reward "
                    f"functions ({len(reward_funcs)})"
                )
            self.reward_weights = torch.tensor(args.reward_weights, dtype=torch.float32)
        else:
            self.reward_weights = torch.ones(len(reward_funcs), dtype=torch.float32)

        # Reward processing class
        if reward_processing_classes is None:
            reward_processing_classes = [None] * len(reward_funcs)
        elif not isinstance(reward_processing_classes, list):
            reward_processing_classes = [reward_processing_classes]
        if len(reward_processing_classes) != len(reward_funcs):
            raise ValueError(
                f"The number of reward processing classes ({len(reward_processing_classes)}) must match the number of "
                f"reward functions ({len(reward_funcs)})."
            )

        for i, (reward_processing_class, reward_func) in enumerate(
            zip(reward_processing_classes, reward_funcs, strict=True)
        ):
            if isinstance(reward_func, PreTrainedModel):
                if reward_processing_class is None:
                    reward_processing_class = AutoTokenizer.from_pretrained(
                        get_config_model_id(reward_func.config), trust_remote_code=args.trust_remote_code
                    )
                if reward_processing_class.pad_token_id is None:
                    reward_processing_class.pad_token = reward_processing_class.eos_token
                # The reward model computes the reward for the latest non-padded token in the input sequence.
                # So it's important to set the pad token ID to the padding token ID of the processing class.
                reward_func.config.pad_token_id = reward_processing_class.pad_token_id
                reward_processing_classes[i] = reward_processing_class

        self.reward_processing_classes = reward_processing_classes

        # Training arguments
        self.max_completion_length = args.max_completion_length
        self.num_generations = args.num_generations
        self.num_generations_eval = args.num_generations_eval or self.num_generations
        self.chat_template_kwargs = args.chat_template_kwargs or {}
        self.temperature = args.temperature
        self.top_p = args.top_p
        self.top_k = args.top_k
        self.min_p = args.min_p
        self.repetition_penalty = args.repetition_penalty
        self.use_transformers_continuous_batching = args.use_transformers_continuous_batching
        if self.use_transformers_continuous_batching:
            if not Version(transformers.__version__) >= Version("5.8.0"):
                raise ImportError(
                    "Using `use_transformers_continuous_batching` requires transformers>=5.8.0. "
                    "Please upgrade with `pip install --upgrade transformers`."
                )
            from transformers.generation import ContinuousBatchingConfig

            cb_kwargs = dict(args.transformers_continuous_batching_config or {})
            # The transformers default [0.9] leaves almost no VRAM for the training backward pass;
            # use a training-aware default unless the user has set it explicitly.
            cb_kwargs.setdefault("max_memory_percent", 0.5)
            self.continuous_batching_config = ContinuousBatchingConfig(**cb_kwargs)
        else:
            self.continuous_batching_config = None
        self.pad_to_multiple_of = args.pad_to_multiple_of
        self.use_vllm = args.use_vllm
        self.vllm_mode = args.vllm_mode
        self.vllm_gpu_memory_utilization = args.vllm_gpu_memory_utilization  # only applies to colocation mode
        self.vllm_tensor_parallel_size = args.vllm_tensor_parallel_size  # only applies to colocation mode
        self.normalize_advantages = args.normalize_advantages
        self.mask_truncated_completions = args.mask_truncated_completions
        self.reward_clip_range = args.reward_clip_range

        # Datasets
        self.shuffle_dataset = args.shuffle_dataset

        if train_dataset is None:
            raise ValueError("`train_dataset` is required")
        elif (
            isinstance(train_dataset, IterableDataset)
            or isinstance(eval_dataset, IterableDataset)
            or (
                isinstance(eval_dataset, dict) and any(isinstance(ds, IterableDataset) for ds in eval_dataset.values())
            )
        ):
            # See https://github.com/huggingface/trl/issues/3213
            raise NotImplementedError(
                "Iterable datasets are not yet supported in RLOOTrainer. Please use a standard dataset instead."
            )

        # Multi-step
        self.num_iterations = args.num_iterations
        self.epsilon_low = args.epsilon
        self.epsilon_high = args.epsilon_high if args.epsilon_high is not None else args.epsilon

        # MoE load-balancing auxiliary loss, applied to Mixture-of-Experts models [no effect otherwise]
        text_config = model.config.get_text_config()
        is_moe = getattr(text_config, "output_router_logits", None) is not None
        self.aux_loss_enabled = is_moe and args.router_aux_loss_coef != 0.0
        self.router_aux_loss_coef = args.router_aux_loss_coef
        # Tracks the number of iterations [forward + backward passes], including those within a grad accum cycle
        self._step = 0
        # Buffer the batch to reuse generated outputs across multiple updates. For more details, see
        # `_get_train_sampler` and `_prepare_inputs`.
        self._buffered_inputs = None

        # Transformers explicitly set use_reentrant=True in the past to silence a PyTorch warning, but the default was
        # never updated once PyTorch switched to recommending use_reentrant=False. Until that change lands upstream
        # [see https://github.com/huggingface/transformers/pull/43203] and is released [most likely in 5.0.0], we
        # default to the recommended non-reentrant behavior here, while preserving any user-provided value.
        if args.gradient_checkpointing and Version(transformers.__version__) < Version("5.0.0"):
            args.gradient_checkpointing_kwargs = args.gradient_checkpointing_kwargs or {}
            args.gradient_checkpointing_kwargs.setdefault("use_reentrant", False)

        super().__init__(
            model=model,
            args=args,
            data_collator=identity,  # No data collation is needed in RLOO
            train_dataset=train_dataset,
            eval_dataset=eval_dataset,
            processing_class=processing_class,
            callbacks=callbacks,
            optimizers=optimizers,
        )

        # Reference model
        self.beta = args.beta
        if self.beta == 0.0:
            # If beta is 0.0, the reference model is not needed
            self.ref_model = None
        elif is_peft_model(model):
            # If PEFT is used, the reference model is not needed since the adapter can be disabled
            # to revert to the initial model.
            self.ref_model = None
        else:
            # For deepspeed, fsdp or non-distributed models, create a reference model from scratch
            model_init_kwargs = args.model_init_kwargs or {}
            # Distributed training requires device_map=None ["auto" fails]
            if self.args.distributed_state.distributed_type in ["MULTI_GPU", "DEEPSPEED"]:
                model_init_kwargs["device_map"] = None
            model_init_kwargs.setdefault("trust_remote_code", args.trust_remote_code)
            self.ref_model = create_model_from_path(get_config_model_id(self.model.config), **model_init_kwargs)

        # Disable dropout in the models
        if args.disable_dropout:
            disable_dropout_in_model(model)
            if self.ref_model is not None:
                disable_dropout_in_model(self.ref_model)

        # Initialize the metrics
        self._metrics = {"train": defaultdict(list), "eval": defaultdict(list)}
        self._total_train_tokens = 0
        self._current_train_step_time = 0.0
        self.log_completions = args.log_completions
        self.log_unique_prompts = args.log_unique_prompts
        self.num_completions_to_print = args.num_completions_to_print
        # Keep logs sized to the generation batch to record only outputs from the latest model update.
        self._logs = {
            "images": deque(maxlen=args.generation_batch_size),
            "prompt": deque(maxlen=args.generation_batch_size),
            "completion": deque(maxlen=args.generation_batch_size),
            "rewards": defaultdict(lambda: deque(maxlen=args.generation_batch_size)),
            "advantages": deque(maxlen=args.generation_batch_size),
            "extra": defaultdict(lambda: deque(maxlen=args.generation_batch_size)),
        }
        # Buffers for user-logged data from reward functions, flushed after gathering
        self._pending_extra_logs = defaultdict(list)
        self._pending_metrics = defaultdict(list)

        # Ensure each process receives a unique seed to prevent duplicate completions when generating with
        # transformers if num_generations exceeds per_device_train_batch_size. We could skip it if we use vLLM, but
        # it's safer to set it in all cases.
        set_seed(args.seed, device_specific=True)

        if self.use_vllm:
            self.vllm_generation = VLLMGeneration(
                model=self.model,
                accelerator=self.accelerator,
                processing_class=self.processing_class,
                mode=args.vllm_mode,
                structured_outputs_regex=args.vllm_structured_outputs_regex,
                server_base_url=args.vllm_server_base_url,
                server_host=args.vllm_server_host,
                server_port=args.vllm_server_port,
                group_port=args.vllm_group_port,
                server_timeout=args.vllm_server_timeout,
                tensor_parallel_size=args.vllm_tensor_parallel_size,
                gpu_memory_utilization=args.vllm_gpu_memory_utilization,
                max_model_length=args.vllm_max_model_length,
                max_num_seqs=args.per_device_train_batch_size
                * args.vllm_tensor_parallel_size
                * args.steps_per_generation,
                enable_sleep_mode=args.vllm_enable_sleep_mode,
                model_impl=args.vllm_model_impl,
                repetition_penalty=self.repetition_penalty,
                temperature=self.temperature,
                top_p=self.top_p,
                top_k=self.top_k,
                min_p=self.min_p,
                max_completion_length=self.max_completion_length,
                logprobs=None,
                generation_kwargs=args.generation_kwargs,
            )
            self._last_loaded_step = -1
        else:
            generation_kwargs = {
                "max_new_tokens": self.max_completion_length,
                "do_sample": True,
                "pad_token_id": self._tokenizer.pad_token_id,
                "bos_token_id": self._tokenizer.bos_token_id,
                "eos_token_id": self._tokenizer.eos_token_id,
                "temperature": self.temperature,
                "top_p": self.top_p,
                "top_k": self.top_k,
                "min_p": self.min_p,
                "repetition_penalty": self.repetition_penalty,
                "cache_implementation": args.cache_implementation,
            }
            if args.generation_kwargs is not None:
                generation_kwargs.update(args.generation_kwargs)
            self.generation_config = GenerationConfig(**generation_kwargs, disable_compile=True)
            # Keep training-specific generation kwargs to overwrite model's original generation config
            self.generation_kwargs = generation_kwargs

        # Gradient accumulation requires scaled loss. Normally, loss scaling in the parent class depends on whether the
        # model accepts loss-related kwargs. Since we compute our own loss, this check is irrelevant. We set
        # self.model_accepts_loss_kwargs to False to enable scaling.
        self.model_accepts_loss_kwargs = False
        self._dist = DistributedBackend(self.accelerator)

        # Add tags to the model
        self.model.add_model_tags(self._tag_names)

        if self.ref_model is not None:
            if self.is_deepspeed_enabled:
                self.ref_model = prepare_deepspeed(self.ref_model, self.accelerator)
            elif self.is_fsdp_enabled:
                self.ref_model = prepare_fsdp(self.ref_model, self.accelerator)
            else:
                self.ref_model = self.accelerator.prepare_model(self.ref_model, evaluation_mode=True)

        if args.sync_ref_model:
            if self.beta == 0.0:
                raise ValueError(
                    "You passed `sync_ref_model=True` while `beta=0.0`, which means the reference model is not used "
                    "during training. Consequently, RLOOTrainer does not create a `ref_model` instance, and there is "
                    "nothing to synchronize. Please set `sync_ref_model=False`, or set `beta` to a non-zero value."
                )
            if is_peft_model(model):
                raise NotImplementedError(
                    "You passed `sync_ref_model=True` while using a PEFT model, which is currently not supported. "
                    "With PEFT, RLOOTrainer does not keep a separate reference model in memory; instead, it recovers "
                    "reference behavior by temporarily disabling the adapter. As a result, there is no standalone "
                    "`ref_model` instance to synchronize. Use `sync_ref_model=False`, or opt for full fine-tuning if "
                    "you need a synced reference model. If you need `sync_ref_model` to work with PEFT, please open a "
                    "feature request at https://github.com/huggingface/trl/issues."
                )
            self.add_callback(SyncRefModelCallback(ref_model=self.ref_model, accelerator=self.accelerator))

        for i, reward_func in enumerate(self.reward_funcs):
            if isinstance(reward_func, PreTrainedModel):
                if self.is_deepspeed_enabled:
                    self.reward_funcs[i] = prepare_deepspeed(reward_func, self.accelerator)
                else:
                    # set device placement to True to make `prepare_model` move `reward_func` to device when using fsdp
                    self.reward_funcs[i] = self.accelerator.prepare_model(
                        reward_func, evaluation_mode=True, device_placement=True
                    )

    def _set_signature_columns_if_needed(self):
        # If `self.args.remove_unused_columns` is True, non-signature columns are removed.
        # By default, this method sets `self._signature_columns` to the model's expected inputs (usually, "input_ids"
        # and "attention_mask"). In RLOOTrainer, we preprocess data, so using the model's signature columns doesn't
        # work. Instead, we set them to the columns expected by the `training_step` method, hence the override.
        if self._signature_columns is None:
            self._signature_columns = ["prompt", "image", "images"]

    # This method overrides `Trainer.get_train_dataloader` to support our custom batching strategy.
    # Instead of returning a standard per-step batch (i.e., `per_device_batch_size), our dataloader loads an
    # *generation* batch (i.e., `per_device_batch_size × steps_per_generation`). This allows us to generate completions
    # once every steps_per_generation step—rather than once per accumulation step—which is significantly more
    # efficient. The only change from the original implementation is multiplying the batch size by
    # `steps_per_generation`. Thus, `_prepare_inputs` is called with this *generation* batch, and it handles the
    # splitting internally.
    # Maintenance note: This method is a copy-paste of the original `Trainer.get_train_dataloader` with only one line
    # modification.
    def get_train_dataloader(self):
        return self._get_dataloader(
            dataset=self.train_dataset,
            description="Training",
            batch_size=self._train_batch_size * self.args.steps_per_generation,  # < this is the change
            sampler_fn=self._get_train_sampler,
            is_training=True,
        )

    def _get_train_sampler(self, dataset: Dataset | None = None) -> Sampler:
        # Returns a sampler that
        # 1. ensures each prompt is repeated across multiple processes. This guarantees that identical prompts are
        #    distributed to different GPUs, allowing rewards to be computed and normalized correctly within each prompt
        #    group. Using the same seed across processes ensures consistent prompt assignment, preventing discrepancies
        #    in group formation.
        # 2. repeats the batch multiple times to allow reusing generations across multiple updates. Refer to
        #    _prepare_inputs to see how the generations are stored and reused.

        # In the following figure, the values are the prompt indices. Each row shows the per-step batch
        # returned by `_prepare_inputs`; rows within a `steps_per_generation` block are slices of the same
        # generated batch. When `num_iterations > 1`, that block is reused for multiple optimization passes
        # before regenerating.
        #
        #                                      |   GPU 0  |   GPU 1  |
        #
        #                 global_step   step    <-───>  num_generations=2
        #                                       <-───────> per_device_train_batch_size=3
        #  grad_accum    ▲  ▲  0          0     0   0   1   1   2   2   <- Generate for the first `steps_per_generation` (prompts 0 to 11); store the completions; use the first slice to compute the loss
        #     =2         ▼  |  0          1     3   3   4   4   5   5   <- Take the stored generations and use the second slice to compute the loss
        #                   |
        #                   |  1          2     6   6   7   7   8   8   <- Take the stored generations and use the third slice to compute the loss
        #  steps_per_gen=4  ▼  1          3     9   9  10  10  11  11   <- Take the stored generations and use the fourth slice to compute the loss
        #
        #                      2          4    12  12  13  13  14  14   <- Generate for the second `steps_per_generation` (prompts 12 to 23); store the completions; use the first slice to compute the loss
        #                      2          5    15  15  16  16  17  17   <- Take the stored generations and use the second slice to compute the loss
        #                                          ...
        if dataset is None:
            dataset = self.train_dataset
        return RepeatSampler(
            data_source=dataset,
            mini_repeat_count=self.num_generations,
            batch_size=self.args.generation_batch_size // self.num_generations,
            repeat_count=self.num_iterations * self.args.steps_per_generation,
            shuffle=self.shuffle_dataset,
            seed=self.args.seed,
        )

    def _get_eval_sampler(self, eval_dataset) -> Sampler:
        # See _get_train_sampler for an explanation of the sampler.
        return RepeatSampler(
            data_source=eval_dataset,
            mini_repeat_count=self.num_generations_eval,
            seed=self.args.seed,
        )

    @profiling_decorator
    def _get_per_token_logps_and_entropies(
        self,
        model,
        input_ids,
        attention_mask,
        logits_to_keep,
        batch_size=None,
        compute_entropy=False,
        compute_aux_loss=False,
        pixel_values=None,
        image_grid_thw=None,
        num_images=None,
        pixel_attention_mask=None,
        spatial_shapes=None,
        num_tiles=None,
        image_sizes=None,
        token_type_ids=None,
        mm_token_type_ids=None,
        image_position_ids=None,
    ) -> tuple[torch.Tensor, torch.Tensor | None, torch.Tensor | None]:
        """Compute log-probs, (optionally) entropies, and (optionally) the MoE load-balancing aux loss."""
        batch_size = batch_size or input_ids.size(0)  # Chunk inputs into smaller batches to reduce memory peak
        all_logps = []
        all_entropies = []
        all_aux_losses = []
        for start in range(0, input_ids.size(0), batch_size):
            input_ids_batch = input_ids[start : start + batch_size]
            attention_mask_batch = attention_mask[start : start + batch_size]

            # Build model inputs
            model_inputs = {"input_ids": input_ids_batch, "attention_mask": attention_mask_batch}
            if image_grid_thw is not None and pixel_values is not None:
                rows_per_image = image_grid_thw.prod(dim=-1)
                rows_per_sample = torch.split(rows_per_image, num_images)
                rows_per_sample = torch.stack([s.sum() for s in rows_per_sample])
                cum_rows = torch.cat([torch.tensor([0], device=rows_per_sample.device), rows_per_sample.cumsum(0)])
                row_start, row_end = cum_rows[start].item(), cum_rows[start + batch_size].item()
                model_inputs["pixel_values"] = pixel_values[row_start:row_end]
                cum_imgs = torch.tensor([0] + num_images).cumsum(0)
                img_start, img_end = cum_imgs[start], cum_imgs[start + batch_size]
                model_inputs["image_grid_thw"] = image_grid_thw[img_start:img_end]
            elif image_position_ids is not None and pixel_values is not None:
                cum_imgs = torch.tensor([0] + num_images).cumsum(0)
                img_start, img_end = cum_imgs[start], cum_imgs[start + batch_size]
                model_inputs["pixel_values"] = pixel_values[img_start:img_end]
                model_inputs["image_position_ids"] = image_position_ids[img_start:img_end]
            elif spatial_shapes is not None and pixel_values is not None:
                # LFM2-VL tensors are tile-indexed.
                cum_tiles = torch.tensor([0] + num_tiles).cumsum(0)
                tile_start, tile_end = cum_tiles[start], cum_tiles[start + batch_size]
                model_inputs["pixel_values"] = pixel_values[tile_start:tile_end]
                model_inputs["pixel_attention_mask"] = pixel_attention_mask[tile_start:tile_end]
                model_inputs["spatial_shapes"] = spatial_shapes[tile_start:tile_end]
            elif pixel_values is not None:
                model_inputs["pixel_values"] = pixel_values[start : start + batch_size]
            if pixel_attention_mask is not None and spatial_shapes is None:
                model_inputs["pixel_attention_mask"] = pixel_attention_mask[start : start + batch_size]
            if image_sizes is not None:
                model_inputs["image_sizes"] = image_sizes[start : start + batch_size]
            if token_type_ids is not None:
                model_inputs["token_type_ids"] = token_type_ids[start : start + batch_size]
            if mm_token_type_ids is not None:
                model_inputs["mm_token_type_ids"] = mm_token_type_ids[start : start + batch_size]

            # Only add logits_to_keep if the model supports it
            if "logits_to_keep" in self.model_kwarg_keys:
                # We add 1 to `logits_to_keep` because the last logits of the sequence is later excluded
                model_inputs["logits_to_keep"] = logits_to_keep + 1

            model_inputs["use_cache"] = False  # only used in generation; set False to suppress warnings

            # MoE models: request router logits so the model returns `outputs.aux_loss`. VLM wrappers honor this only
            # as a forward kwarg (not from the model config), so it must be passed here.
            if compute_aux_loss:
                model_inputs["output_router_logits"] = True

            outputs = model(**model_inputs)
            logits = outputs.logits
            # Exclude the last value: it corresponds to the next token pred
            logits = logits[:, :-1, :]  # (B, L-1, H)
            # Only keep the last logits_to_keep. For model that support logits_to_keep, this is a no-op.
            logits = logits[:, -logits_to_keep:, :]  # (B, logits_to_keep, H)
            # Divide logits by sampling temperature.
            # See https://huggingface.co/blog/the_n_implementation_details_of_rlhf_with_ppo#policy-training-implementation-details
            logits.div_(self.temperature)
            completion_ids = input_ids_batch[:, -logits_to_keep:]
            logps = selective_log_softmax(logits, completion_ids)  # compute logprobs
            all_logps.append(logps)

            if compute_entropy:
                with torch.no_grad():
                    entropies = entropy_from_logits(logits)
                all_entropies.append(entropies)

            if compute_aux_loss:
                all_aux_losses.append(outputs.aux_loss)

        logps = torch.cat(all_logps, dim=0)
        entropies = torch.cat(all_entropies, dim=0) if compute_entropy else None
        aux_loss = torch.stack(all_aux_losses).mean() if compute_aux_loss else None
        return logps, entropies, aux_loss

    def training_step(self, model, inputs, num_items_in_batch):
        time_before = time.perf_counter()
        output = super().training_step(model, inputs, num_items_in_batch)
        self._step += 1
        time_after = time.perf_counter()
        self._current_train_step_time += time_after - time_before
        if self._step % self.current_gradient_accumulation_steps == 0:
            self._metrics["train"]["step_time"].append(self._current_train_step_time)
            self._current_train_step_time = 0.0
        return output

    @profiling_decorator
    def _prepare_inputs(self, generation_batch: dict[str, torch.Tensor | Any]) -> dict[str, torch.Tensor | Any]:
        # Prepares inputs for model training/evaluation by managing completion generation and batch handling.
        # During training:
        #   - Receives the local generation batch (Per-GPU batch size × steps per generation)
        #     from the modified training dataloader instead of the standard local batch
        #   - Generates completions once for the entire generation batch and splits it into batches of size
        #     `per_device_train_batch_size`
        #   - Buffers these completions and returns the appropriate slice for the current accumulation step
        #   - Optimizes by regenerating completions only periodically (every steps_per_generation * num_iterations)
        # During evaluation:
        #   - The input is treated as a standard local batch (no accumulation, no multiple iterations)
        #   - Completions are generated for each batch without buffering or reuse
        # Returns a single local batch in both cases.

        mode = "train" if self.model.training else "eval"
        if mode == "train":
            generate_every = self.args.steps_per_generation * self.num_iterations
            if self._step % generate_every == 0 or self._buffered_inputs is None:
                # self._buffered_inputs=None can occur when resuming from a checkpoint
                generation_batch = self._generate_and_score_completions(generation_batch)
                generation_batch = split_pixel_values_by_grid(generation_batch)

                try: generation_batch = shuffle_sequence_dict(generation_batch)

                except: pass
                generation_batches = split_tensor_dict(generation_batch, self.args.steps_per_generation)
                self._buffered_inputs = [unsplit_pixel_values_by_grid(batch) for batch in generation_batches]
            inputs = self._buffered_inputs[self._step % self.args.steps_per_generation]
        else:
            # In evaluation, there is neither batch grouping for generation, nor multiple iterations, hence
            # local generation batch == local eval batch
            inputs = self._generate_and_score_completions(generation_batch)
        return inputs

    def _log_completion_extra(self, column: str, values: list):
        """
        Log extra columns to the completions table. Called from reward functions via the `log_extra` kwarg.

        Args:
            column (`str`):
                Name of the column to add.
            values (`list`):
                Values for the column, one per sample in the batch.
        """
        self._pending_extra_logs[column].extend(values)

    def _log_metric(self, name: str, value: float):
        """
        Log a scalar metric from a reward function. Called via the `log_metric` kwarg. Values are averaged over each
        logging step and reported alongside built-in metrics like `kl` and `entropy`.

        Args:
            name (`str`):
                Name of the metric.
            value (`float`):
                Scalar value for this batch.
        """
        self._pending_metrics[name].append(value)

    @profiling_decorator
    def _calculate_rewards(self, inputs, prompts, completions, completion_ids_list):
        device = self.accelerator.device
        rewards_per_func = torch.zeros(len(prompts), len(self.reward_funcs), device=device)

        # Repeat all input columns (but "prompt", "completion", and "completion_ids") to match the num of generations
        keys = [key for key in inputs[0] if key not in ["prompt", "completion", "completion_ids"]]
        reward_kwargs = {key: [example[key] for example in inputs] for key in keys}

        # This allows for dynamic reward shaping based on training progress.
        reward_kwargs["trainer_state"] = self.state

        # Allow reward functions to log extra columns to the completions table.
        reward_kwargs["log_extra"] = self._log_completion_extra

        # Allow reward functions to log additional scalar metrics.
        reward_kwargs["log_metric"] = self._log_metric

        async_funcs_info = []  # async custom functions for asyncio.gather

        for i, (reward_func, reward_processing_class, reward_func_name) in enumerate(
            zip(self.reward_funcs, self.reward_processing_classes, self.reward_func_names, strict=True)
        ):
            if isinstance(reward_func, nn.Module):  # Module (no PretrainedModel) for compat with compiled models
                with profiling_context(self, reward_func_name):
                    if is_conversational(inputs[0]):
                        messages = [{"messages": p + c} for p, c in zip(prompts, completions, strict=True)]
                        texts = [
                            apply_chat_template(x, reward_processing_class, **self.chat_template_kwargs)["text"]
                            for x in messages
                        ]
                    else:
                        texts = [p + c for p, c in zip(prompts, completions, strict=True)]
                    reward_inputs = reward_processing_class(
                        text=texts, return_tensors="pt", padding=True, padding_side="right", add_special_tokens=False
                    )
                    reward_inputs = super()._prepare_inputs(reward_inputs)
                    with torch.inference_mode():
                        rewards_per_func[:, i] = reward_func(**reward_inputs).logits[:, 0]  # Shape (B*G,)
            elif inspect.iscoroutinefunction(reward_func):  # Separate async reward funcs to run them in parallel later
                async_funcs_info.append((i, reward_func, reward_func_name))
            else:
                # Run synchronous reward function
                with profiling_context(self, reward_func_name):
                    output_reward_func = reward_func(
                        prompts=prompts, completions=completions, completion_ids=completion_ids_list, **reward_kwargs
                    )
                    # Convert None values to NaN
                    output_reward_func = [reward if reward is not None else torch.nan for reward in output_reward_func]
                    rewards_per_func[:, i] = torch.tensor(output_reward_func, dtype=torch.float32, device=device)

        # Execute async custom functions in parallel using asyncio.gather
        if async_funcs_info:

            async def _invoke_async(index, func, func_name):
                with profiling_context(self, func_name):
                    output = await func(
                        prompts=prompts, completions=completions, completion_ids=completion_ids_list, **reward_kwargs
                    )
                    output = [r if r is not None else torch.nan for r in output]
                    return index, output

            async def _run_async_funcs():
                coros = [_invoke_async(i, func, func_name) for (i, func, func_name) in async_funcs_info]
                return await asyncio.gather(*coros)

            async_results = asyncio.run_coroutine_threadsafe(_run_async_funcs(), self.async_loop).result()
            for idx, output_reward_func in async_results:
                rewards_per_func[:, idx] = torch.tensor(output_reward_func, dtype=torch.float32, device=device)

        # If all reward functions return None for a given row, issue a detailed warning
        if torch.isnan(rewards_per_func).all(dim=1).any():
            nan_row_idx = torch.isnan(rewards_per_func).all(dim=1).nonzero(as_tuple=True)[0][0]
            row_reward_kwargs = {
                key: value[nan_row_idx]
                for key, value in reward_kwargs.items()
                if key not in ("trainer_state", "log_extra", "log_metric")
            }
            row_reward_kwargs["prompt"] = prompts[nan_row_idx]
            row_reward_kwargs["completion"] = completions[nan_row_idx]
            logger.warning(
                f"All reward functions returned None for the following kwargs:\n{row_reward_kwargs}\n"
                "Please ensure that at least one reward function returns a valid reward."
            )

        # Gather the reward per function: this part is crucial, because the rewards are normalized per group and the
        # completions may be distributed across processes
        rewards_per_func = gather(rewards_per_func)
        return rewards_per_func

    def _tokenize_prompts(self, prompts: list):
        """Tokenize prompts and extract images/multimodal fields for generation."""
        if is_conversational({"prompt": prompts[0]}):
            # Extract images from messages for VLM support
            images = []
            has_images = False
            for prompt in prompts:
                prompt_images = []
                for message in prompt:
                    if isinstance(message["content"], list):
                        for part in message["content"]:
                            if part["type"] == "image":
                                prompt_images.append(part["image"])
                                has_images = True
                images.append(prompt_images if prompt_images else None)
            images = images if has_images else None

            # Workaround for a bug in transformers 5.3.0 where some processors (e.g. Qwen2.5-VL) crash on
            # batched unpadded input (transformers#44514).
            # Fixed in transformers 5.4.0 (transformers#44563).
            needs_padding_workaround = Version("5.3.0") <= Version(transformers.__version__) < Version("5.4.0")
            tokenized = self.processing_class.apply_chat_template(
                conversation=prompts,
                add_generation_prompt=True,
                tokenize=True,
                return_dict=True,
                **({"padding": True} if needs_padding_workaround else {}),
                **self.chat_template_kwargs,
            )
            if needs_padding_workaround:
                # Unpad input_ids: remove padding tokens using attention_mask to get per-sequence lists
                prompt_ids = [
                    [tok for tok, m in zip(ids, mask, strict=True) if m]
                    for ids, mask in zip(tokenized["input_ids"], tokenized["attention_mask"], strict=True)
                ]
            else:
                prompt_ids = tokenized["input_ids"]
            # For VLMs, the processor returns extra multimodal fields (pixel_values, image_grid_thw, etc.)
            multimodal_fields = {k: v for k, v in tokenized.items() if k not in ("input_ids", "attention_mask")}
        else:
            prompt_ids = self.processing_class(text=prompts)["input_ids"]
            images = None
            multimodal_fields = {}
        return prompt_ids, images, multimodal_fields

    def _generate_single_turn(self, prompt_ids, images, multimodal_fields):
        device = self.accelerator.device
        mode = "train" if self.model.training else "eval"

        # Generate completions using either vLLM or regular generation
        if self.use_vllm:
            # Sync weights if training step changed
            if self.state.global_step != self._last_loaded_step:
                with profiling_context(self, "sync_weights"):
                    self.vllm_generation.sync_weights()
                self._last_loaded_step = self.state.global_step

            # Generate using vLLM (note: RLOO doesn't use logprobs from generation, so we ignore them)
            num_generations = self.num_generations if mode == "train" else self.num_generations_eval
            _, completion_ids, _, _ = self.vllm_generation.generate(
                prompts=prompt_ids,
                images=images,
                num_generations=num_generations,
                profiler=profiling_context(self, "vLLM.generate"),
            )

        elif self.use_transformers_continuous_batching:
            with (
                profiling_context(self, "transformers.generate_batch"),
                unwrap_model_for_generation(
                    self.model_wrapped, self.accelerator, gather_deepspeed3_params=self.args.ds3_gather_for_generation
                ) as unwrapped_model,
                torch.no_grad(),
                self._dist.summon_full_params(self.model_wrapped, recurse=False),
            ):
                # Cast to the appropriate dtype based on training configuration
                if self.args.bf16:
                    unwrapped_model.to(torch.bfloat16)
                elif self.args.fp16:
                    unwrapped_model.to(torch.float16)
                all_outputs = unwrapped_model.generate_batch(
                    prompt_ids,
                    generation_config=self.generation_config,
                    continuous_batching_config=self.continuous_batching_config,
                    progress_bar=False,
                )
                unwrapped_model.train()
            completion_ids = [output.generated_tokens for output in all_outputs.values()]

        else:
            # Regular generation path: left-pad token IDs into tensors
            prompt_tensors = [torch.tensor(ids) for ids in prompt_ids]
            padded_ids = pad(prompt_tensors, padding_value=self._tokenizer.pad_token_id, padding_side="left")
            attention_mask = pad([torch.ones_like(t) for t in prompt_tensors], padding_value=0, padding_side="left")
            generate_inputs = {"input_ids": padded_ids, "attention_mask": attention_mask}
            # For VLMs, include multimodal fields as tensors (pixel_values, image_grid_thw, etc.)
            for k, v in multimodal_fields.items():
                if isinstance(v, torch.Tensor):
                    generate_inputs[k] = v
                elif isinstance(v, list) and v and isinstance(v[0], list):
                    # Per-token field (e.g., token_type_ids): left-pad like input_ids
                    generate_inputs[k] = pad([torch.tensor(x) for x in v], padding_value=0, padding_side="left")
                else:
                    generate_inputs[k] = torch.tensor(np.array(v))
            generate_inputs = super()._prepare_inputs(generate_inputs)

            with (
                profiling_context(self, "transformers.generate"),
                unwrap_model_for_generation(
                    self.model_wrapped,
                    self.accelerator,
                    gather_deepspeed3_params=self.args.ds3_gather_for_generation,
                    generation_kwargs=self.generation_kwargs,  # Override model.generation_config with generation_kwargs to fix transformers#42762
                ) as unwrapped_model,
                torch.no_grad(),
                self._dist.summon_full_params(self.model_wrapped, recurse=False),
            ):
                prompt_completion_ids = unwrapped_model.generate(
                    **generate_inputs, generation_config=self.generation_config
                )
            # Compute prompt length and extract completion ids
            prompt_length = generate_inputs["input_ids"].size(1)
            completion_ids = prompt_completion_ids[:, prompt_length:]

            # Mask everything after the first EOS token
            is_eos = completion_ids == self._tokenizer.eos_token_id
            eos_idx = torch.full((is_eos.size(0),), is_eos.size(1), dtype=torch.long, device=device)
            eos_idx[is_eos.any(dim=1)] = is_eos.int().argmax(dim=1)[is_eos.any(dim=1)]
            sequence_indices = torch.arange(is_eos.size(1), device=device).expand(is_eos.size(0), -1)
            completion_mask = (sequence_indices <= eos_idx.unsqueeze(1)).int()
            completion_ids = [
                c[m].tolist() for c, m in zip(completion_ids.cpu(), completion_mask.bool().cpu(), strict=True)
            ]

        return completion_ids

    def _generate(self, prompts: list):
        device = self.accelerator.device
        mode = "train" if self.model.training else "eval"

        # Copy the prompts to avoid modifying the original list
        prompts = copy.deepcopy(prompts)

        prompt_ids, images, multimodal_fields = self._tokenize_prompts(prompts)
        completion_ids = self._generate_single_turn(prompt_ids, images, multimodal_fields)

        # Decode completions. It's important to use `parse_response` when possible, because it handles tool calls.
        if is_conversational({"prompt": prompts[0]}):
            contents = self.processing_class.batch_decode(completion_ids, skip_special_tokens=True)
            completions = [[{"role": "assistant", "content": content}] for content in contents]
        else:
            completions = self.processing_class.batch_decode(completion_ids, skip_special_tokens=True)

        # Get completion length per sequence, used for logging
        prompt_lengths = torch.tensor([len(ids) for ids in prompt_ids], device=device)
        completion_lengths = torch.tensor([len(ids) for ids in completion_ids], device=device)
        agg_prompt_lengths = self.accelerator.gather(prompt_lengths)
        agg_completion_lengths = self.accelerator.gather(completion_lengths)
        total_prompt_tokens = agg_prompt_lengths.sum()
        total_completion_tokens = agg_completion_lengths.sum()  # = num_items_in_batch, required for the DAPO loss

        # Log the metrics
        if mode == "train":
            self.state.num_input_tokens_seen += (total_prompt_tokens + total_completion_tokens).item()
        self._metrics[mode]["num_tokens"] = [self.state.num_input_tokens_seen]

        # Log completion lengths, mean, min, max
        self._metrics[mode]["completions/mean_length"].append(agg_completion_lengths.float().mean().item())
        self._metrics[mode]["completions/min_length"].append(agg_completion_lengths.float().min().item())
        self._metrics[mode]["completions/max_length"].append(agg_completion_lengths.float().max().item())

        # Identify sequences that terminated with EOS and log their lengths
        eos_and_pad = [self._tokenizer.eos_token_id, self._tokenizer.pad_token_id]
        is_truncated = torch.tensor([ids[-1] not in eos_and_pad for ids in completion_ids], device=device)
        agg_is_truncated = self.accelerator.gather(is_truncated)
        self._metrics[mode]["completions/clipped_ratio"].append(agg_is_truncated.float().mean().item())
        term_completion_lengths = agg_completion_lengths[~agg_is_truncated]
        if len(term_completion_lengths) == 0:  # edge case where no terminated sequences are found
            term_completion_lengths = torch.zeros(1, device=device)
        self._metrics[mode]["completions/mean_terminated_length"].append(term_completion_lengths.float().mean().item())
        self._metrics[mode]["completions/min_terminated_length"].append(term_completion_lengths.float().min().item())
        self._metrics[mode]["completions/max_terminated_length"].append(term_completion_lengths.float().max().item())

        return prompt_ids, completion_ids, completions

    def _generate_and_score_completions(
        self, inputs: list[dict[str, torch.Tensor | Any]]
    ) -> dict[str, torch.Tensor | Any]:
        device = self.accelerator.device
        mode = "train" if self.model.training else "eval"

        prompts = [x["prompt"] for x in inputs]

        if "images" in inputs[0]:
            images = [example.get("images") for example in inputs]
        elif "image" in inputs[0]:
            images = [[example.get("image")] if example.get("image") is not None else None for example in inputs]
        else:
            images = None
        # Transformers requires at least one image in the batch, otherwise it throws an error
        if images is not None and all(img_list == [] for img_list in images):
            images = None

        # If the prompts are conversational and the inputs contain images, we need to convert the prompts from
        # [{"role": "user", "content": "What color is the sky?"}] to
        # [{"role": "user", "content": [{"type": "image", "image": <Image>}, {"type": "text", "text": "What color is the sky?"}]}]
        if images is not None:
            if not is_conversational(inputs[0]):
                raise ValueError(
                    "Multimodal training requires conversational prompts. It looks like the dataset contains "
                    "non-conversational inputs, likely because a chat template was applied before passing the dataset "
                    "to the trainer. Please provide the raw conversational prompts and let the trainer apply the chat "
                    "template internally."
                )
            prompts = [
                prepare_multimodal_messages(prompt, images=image_list)
                for prompt, image_list in zip(prompts, images, strict=True)
            ]

        prompt_ids_list, completion_ids_list, completions = self._generate(prompts)

        # Convert lists of token IDs to padded tensors
        prompt_ids = [torch.tensor(ids) for ids in prompt_ids_list]
        prompt_mask = [torch.ones_like(ids, dtype=torch.long) for ids in prompt_ids]
        prompt_ids = pad(
            prompt_ids,
            padding_value=self._tokenizer.pad_token_id,
            padding_side="left",
            pad_to_multiple_of=self.pad_to_multiple_of,
        ).to(device=device)
        prompt_mask = pad(
            prompt_mask, padding_value=0, padding_side="left", pad_to_multiple_of=self.pad_to_multiple_of
        ).to(device=device)
        completion_ids = [torch.tensor(ids) for ids in completion_ids_list]
        completion_mask = [torch.ones_like(ids, dtype=torch.long) for ids in completion_ids]
        completion_ids = pad(
            completion_ids,
            padding_value=self._tokenizer.pad_token_id,
            padding_side="right",
            pad_to_multiple_of=self.pad_to_multiple_of,
        ).to(device=device)
        completion_mask = pad(
            completion_mask, padding_value=0, padding_side="right", pad_to_multiple_of=self.pad_to_multiple_of
        ).to(device=device)

        # If mask_truncated_completions is enabled, zero out truncated completions in completion_mask
        if self.mask_truncated_completions:
            eos_and_pad = [self._tokenizer.eos_token_id, self._tokenizer.pad_token_id]
            # Mask completion_mask for attention masking
            is_truncated = torch.tensor([ids[-1] not in eos_and_pad for ids in completion_ids_list], device=device)
            completion_mask = completion_mask * (~is_truncated).unsqueeze(1).int()

        # Concatenate prompt_mask with completion_mask for logit computation
        prompt_completion_ids = torch.cat([prompt_ids, completion_ids], dim=1)  # (B, P+C)
        attention_mask = torch.cat([prompt_mask, completion_mask], dim=1)  # (B, P+C)

        logits_to_keep = completion_ids.size(1)  # we only need to compute the logits for the completion tokens
        batch_size = self.args.per_device_train_batch_size if mode == "train" else self.args.per_device_eval_batch_size

        num_images = [len(img_list) if img_list else 0 for img_list in images] if images is not None else None

        # Get forward_kwargs for models with multimodal inputs
        if images is not None:
            prompts_text = [
                apply_chat_template({"prompt": prompt}, self.processing_class, **self.chat_template_kwargs)["prompt"]
                for prompt in prompts
            ]
            prompt_inputs = self.processing_class(images=images, text=prompts_text, padding=True, return_tensors="pt")
            prompt_inputs = super()._prepare_inputs(prompt_inputs)
            forward_kwargs = {k: v for k, v in prompt_inputs.items() if k not in ["input_ids", "attention_mask"]}
        else:
            forward_kwargs = {}

        # Recover LFM2-VL tile counts; the full processor drops row/column metadata.
        num_tiles = None
        if images is not None and "spatial_shapes" in forward_kwargs:
            image_info = self.processing_class.image_processor(
                images=images, return_tensors="pt", return_row_col_info=True
            )
            tiles_per_image = image_info["image_rows"] * image_info["image_cols"]
            if self.processing_class.image_processor.use_thumbnail:
                tiles_per_image = tiles_per_image + (tiles_per_image > 1).to(tiles_per_image.dtype)
            num_tiles = [group.sum().item() for group in torch.split(tiles_per_image, num_images)]

        # If token_type_ids are used, extend them with zeros for the completion part
        if "token_type_ids" in forward_kwargs:
            token_type_ids = forward_kwargs["token_type_ids"]
            if self.pad_to_multiple_of is not None:
                # Needed only with pad_to_multiple_of: otherwise prompt_ids and token_type_ids must have equal len
                padding_size = prompt_ids.size(1) - token_type_ids.size(1)
                if padding_size > 0:
                    token_type_ids = torch.cat(
                        [token_type_ids.new_zeros((token_type_ids.size(0), padding_size)), token_type_ids], dim=1
                    )
            forward_kwargs["token_type_ids"] = torch.cat(
                [token_type_ids, token_type_ids.new_zeros(completion_ids.shape)], dim=1
            )
        # If mm_token_type_ids are used, extend them with zeros for the completion part
        if "mm_token_type_ids" in forward_kwargs:
            mm_token_type_ids = forward_kwargs["mm_token_type_ids"]
            if self.pad_to_multiple_of is not None:
                # Needed only with pad_to_multiple_of: otherwise prompt_ids and mm_token_type_ids must have equal len
                padding_size = prompt_ids.size(1) - mm_token_type_ids.size(1)
                if padding_size > 0:
                    mm_token_type_ids = torch.cat(
                        [mm_token_type_ids.new_zeros((mm_token_type_ids.size(0), padding_size)), mm_token_type_ids],
                        dim=1,
                    )
            forward_kwargs["mm_token_type_ids"] = torch.cat(
                [mm_token_type_ids, mm_token_type_ids.new_zeros(completion_ids.shape)], dim=1
            )

        # When gradient checkpointing is enabled with use_reentrant=True (non default), calling the model inside a
        # torch.no_grad() block triggers a harmless PyTorch warning ("None of the inputs have requires_grad=True").
        # Temporarily disable checkpointing to avoid this warning during inference.
        with torch.no_grad(), disable_gradient_checkpointing(self.model, self.args.gradient_checkpointing_kwargs):
            # Compute the per-token log probabilities for the current model
            old_per_token_logps, _, _ = self._get_per_token_logps_and_entropies(
                self.model,
                prompt_completion_ids,
                attention_mask,
                logits_to_keep,
                batch_size,
                num_images=num_images,
                num_tiles=num_tiles,
                **forward_kwargs,  # may contain pixel_values, image_grid_thw, pixel_attention_mask, spatial_shapes, image_sizes, image_position_ids
            )
            old_logps = (old_per_token_logps * completion_mask).sum(1)  # mask out padding and tokens after EOS

            # Compute the per-token log probabilities for the reference model
            if self.beta != 0.0:
                if self.ref_model is not None:
                    ref_per_token_logps, _, _ = self._get_per_token_logps_and_entropies(
                        self.ref_model,
                        prompt_completion_ids,
                        attention_mask,
                        logits_to_keep,
                        batch_size=batch_size,
                        num_images=num_images,
                        num_tiles=num_tiles,
                        **forward_kwargs,  # may contain pixel_values, image_grid_thw, pixel_attention_mask, spatial_shapes, image_sizes, image_position_ids
                    )
                else:
                    # When training a PEFT adapter, how we obtain the reference depends on the setup:
                    # - New adapter: disabling adapters yields the base model.
                    # - Re-training an existing adapter: an initial copy is loaded under the name "ref".
                    model = self.accelerator.unwrap_model(self.model)
                    with use_adapter(model, adapter_name="ref" if "ref" in model.peft_config else None):
                        ref_per_token_logps, _, _ = self._get_per_token_logps_and_entropies(
                            self.model,
                            prompt_completion_ids,
                            attention_mask,
                            logits_to_keep,
                            batch_size=batch_size,
                            num_images=num_images,
                            num_tiles=num_tiles,
                            **forward_kwargs,  # may contain pixel_values, image_grid_thw, pixel_attention_mask, spatial_shapes, image_sizes, image_position_ids
                        )
            else:
                ref_per_token_logps = None

        # Decode
        prompts_text = self.processing_class.batch_decode(prompt_ids, skip_special_tokens=True)
        completions_text = self.processing_class.batch_decode(completion_ids, skip_special_tokens=True)

        # Calculate rewards for each reward function. rewards_per_func aggregates rewards across all processes. This is
        # important because rewards will be normalized per group, and completions are distributed. We will later slice
        # rewards_per_func to extract each process's subset.
        rewards_per_func = self._calculate_rewards(inputs, prompts, completions, completion_ids_list)
        num_generations = self.num_generations if mode == "train" else self.num_generations_eval

        # A completion for which every reward function returned None is unscorable. nansum would collapse it to 0,
        # which both biases the leave-one-out baseline and hands the completion a spurious advantage. Mark these rows
        # NaN so they're excluded from the (nan-aware) baseline below; their advantage is forced to 0 afterwards.
        unscorable_mask = torch.isnan(rewards_per_func).all(dim=1)

        # Apply weights to each reward function's output and sum
        rewards = (rewards_per_func * self.reward_weights.to(device).unsqueeze(0)).nansum(dim=1)
        rewards[unscorable_mask] = torch.nan

        # Apply reward clipping if specified
        if self.reward_clip_range:
            rewards = rewards.clamp(min=self.reward_clip_range[0], max=self.reward_clip_range[1])

        # Include the KL penalty in the reward
        if self.beta != 0.0:
            # RLOO uses the first-order log ratio for the per-token KL estimate, following the original RLOO paper
            # (Ahmadian et al., 2024, https://huggingface.co/papers/2405.14782). Unlike GRPOTrainer's Schulman
            # approximation (always >= 0), this can be negative per token. The divergence is intentional: RLOO applies
            # KL as a reward penalty (summed across tokens per sequence), while GRPO adds it to the per-token loss.
            per_token_kl = old_per_token_logps - ref_per_token_logps
            # Apply sequence-level KL penalty to rewards (sum KL across tokens first, then apply to each sequence)
            kl = (per_token_kl * completion_mask).sum(-1)
            kl = gather(kl)  # rewards are gathered, so kl must be too
            rewards = rewards - self.beta * kl

        grouped_rewards = rewards.view(-1, num_generations)
        mean_grouped_rewards = torch.nanmean(grouped_rewards, dim=1)
        if num_generations > 1:
            std_rewards = nanstd(grouped_rewards, dim=1)
        else:  # doesn't occur during training, but could occur in eval when num_generations_eval=1
            std_rewards = torch.zeros_like(mean_grouped_rewards)

        # RLOO advantages computation. The leave-one-out baseline averages over scorable siblings only: nansum drops
        # unscorable rewards and the divisor is (scorable count − 1). A group with a single scorable completion yields
        # 0/0 = NaN, and unscorable rows stay NaN; both are zeroed by nan_to_num below.
        scorable_counts = (~torch.isnan(grouped_rewards)).sum(dim=1, keepdim=True)  # (num_prompts, 1)
        grouped_sum = torch.nansum(grouped_rewards, dim=1, keepdim=True)  # (num_prompts, 1)
        if num_generations > 1:
            baselines = (grouped_sum - grouped_rewards) / (scorable_counts - 1)  # (num_prompts, num_generations)
            baselines = baselines.view(-1)  # Flatten back to match rewards shape
            advantages = rewards - baselines
        else:  # this case doesn't occur during training, but could in eval when num_generations_eval=1
            advantages = torch.zeros_like(rewards)

        # Normalize advantages over the scorable subset only (unscorable advantages are still NaN here).
        if self.normalize_advantages:
            advantages = (advantages - torch.nanmean(advantages)) / (nanstd(advantages) + 1e-4)

        # Unscorable completions carry no learning signal: zero their advantage to keep them from moving the policy.
        advantages = torch.nan_to_num(advantages, nan=0.0)

        is_std_zero = torch.isclose(std_rewards, torch.zeros_like(std_rewards))  # for logging

        # Slice to keep only the local part of the data
        process_slice = slice(
            self.accelerator.process_index * len(prompts),
            (self.accelerator.process_index + 1) * len(prompts),
        )
        all_process_advantages = advantages.clone()  # keep the aggregated advantages for logging
        advantages = advantages[process_slice]

        # Calculate and log the mean KL divergence between current and reference model
        if self.beta != 0.0:
            mean_kl = (per_token_kl * completion_mask).sum() / completion_mask.sum().clamp(min=1.0)
            self._metrics[mode]["kl"].append(self.accelerator.gather(mean_kl).nanmean().item())

        # Calculate mean reward per function, but only for samples where the function was applied (non-NaN values)
        for i, reward_func_name in enumerate(self.reward_func_names):
            mean_rewards = torch.nanmean(rewards_per_func[:, i]).item()
            self._metrics[mode][f"rewards/{reward_func_name}/mean"].append(mean_rewards)
            std_func_rewards = nanstd(rewards_per_func[:, i]).item()
            self._metrics[mode][f"rewards/{reward_func_name}/std"].append(std_func_rewards)
        rewards = (rewards_per_func * self.reward_weights.to(rewards_per_func.device).unsqueeze(0)).nansum(dim=1)
        rewards[unscorable_mask] = torch.nan  # exclude unscorable rows from the logged reward stats
        self._metrics[mode]["reward"].append(torch.nanmean(rewards).item())
        self._metrics[mode]["reward_std"].append(nanstd(rewards).item())
        self._metrics[mode]["frac_reward_zero_std"].append(is_std_zero.float().mean().item())

        # Log prompt and completion texts
        self._logs["prompt"].extend(gather_object(prompts_text))
        self._logs["completion"].extend(gather_object(completions_text))
        for i, name in enumerate(self.reward_func_names):
            self._logs["rewards"][name].extend(rewards_per_func[:, i].tolist())
        self._logs["advantages"].extend(all_process_advantages.tolist())

        # Flush user-logged extra columns (from log_extra), gathering across processes.
        # Keys must be sorted so that all ranks call gather_object in the same order, otherwise values
        # get mis-attributed across columns (dict insertion order may differ between processes).
        for column in sorted(self._pending_extra_logs):
            self._logs["extra"][column].extend(gather_object(self._pending_extra_logs[column]))
        self._pending_extra_logs.clear()

        # Flush user-logged metrics (from log_metric), averaging across processes.
        # Keys must be sorted so that all ranks call accelerator.gather in the same order, otherwise values
        # get mis-attributed across metrics (dict insertion order may differ between processes).
        for name in sorted(self._pending_metrics):
            values = self._pending_metrics[name]
            local_mean = sum(values) / len(values)
            global_mean = self.accelerator.gather(torch.tensor(local_mean, device=device)).mean().item()
            self._metrics[mode][name].append(global_mean)
        self._pending_metrics.clear()

        if images is not None:
            self._logs["images"].extend(gather_object(images))

        output = {
            "prompt_ids": prompt_ids,
            "prompt_mask": prompt_mask,
            "completion_ids": completion_ids,
            "completion_mask": completion_mask,
            "old_logps": old_logps,
            "advantages": advantages,
        }
        if "pixel_values" in forward_kwargs:
            output["pixel_values"] = forward_kwargs["pixel_values"]
        if "image_grid_thw" in forward_kwargs:
            output["image_grid_thw"] = forward_kwargs["image_grid_thw"]
        if "pixel_attention_mask" in forward_kwargs:
            output["pixel_attention_mask"] = forward_kwargs["pixel_attention_mask"]
        if "spatial_shapes" in forward_kwargs:
            output["spatial_shapes"] = forward_kwargs["spatial_shapes"]
        if "image_sizes" in forward_kwargs:
            output["image_sizes"] = forward_kwargs["image_sizes"]
        if "token_type_ids" in forward_kwargs:
            output["token_type_ids"] = forward_kwargs["token_type_ids"]
        if "mm_token_type_ids" in forward_kwargs:
            output["mm_token_type_ids"] = forward_kwargs["mm_token_type_ids"]
        if "image_position_ids" in forward_kwargs:
            output["image_position_ids"] = forward_kwargs["image_position_ids"]
        if images is not None:
            output["num_images"] = num_images
            if num_tiles is not None:
                output["num_tiles"] = num_tiles
        return output

    @profiling_decorator
    def compute_loss(self, model, inputs, return_outputs=False, num_items_in_batch=None):
        if return_outputs:
            raise ValueError("The RLOOTrainer does not support returning outputs")
        return self._compute_loss(model, inputs)

    def _compute_loss(self, model, inputs):
        # Compute the per-token log probabilities for the model
        prompt_ids, prompt_mask = inputs["prompt_ids"], inputs["prompt_mask"]
        completion_ids, completion_mask = inputs["completion_ids"], inputs["completion_mask"]
        input_ids = torch.cat([prompt_ids, completion_ids], dim=1)
        attention_mask = torch.cat([prompt_mask, completion_mask], dim=1)
        logits_to_keep = completion_ids.size(1)  # we only need to compute the logits for the completion tokens

        # Compute the per_token_logps and the entropy at each position in the completion
        per_token_logps, entropies, aux_loss = self._get_per_token_logps_and_entropies(
            model,
            input_ids,
            attention_mask,
            logits_to_keep,
            compute_entropy=True,
            compute_aux_loss=self.aux_loss_enabled,
            pixel_values=inputs.get("pixel_values"),
            image_grid_thw=inputs.get("image_grid_thw"),
            num_images=inputs.get("num_images"),
            pixel_attention_mask=inputs.get("pixel_attention_mask"),
            spatial_shapes=inputs.get("spatial_shapes"),
            num_tiles=inputs.get("num_tiles"),
            image_sizes=inputs.get("image_sizes"),
            token_type_ids=inputs.get("token_type_ids"),
            mm_token_type_ids=inputs.get("mm_token_type_ids"),
            image_position_ids=inputs.get("image_position_ids"),
        )

        logps = (per_token_logps * completion_mask).sum(1)  # mask out padding and tokens after EOS
        old_logps = inputs["old_logps"]
        log_ratio = logps - old_logps

        # Compute the loss
        advantages = inputs["advantages"]
        coef_1 = torch.exp(log_ratio)
        coef_2 = torch.clamp(coef_1, 1 - self.epsilon_low, 1 + self.epsilon_high)
        per_sequence_loss1 = coef_1 * advantages
        per_sequence_loss2 = coef_2 * advantages
        per_sequence_loss = -torch.min(per_sequence_loss1, per_sequence_loss2)
        loss = per_sequence_loss.mean()

        # Log the metrics
        mode = "train" if self.model.training else "eval"

        # RLOO returns an unscaled loss (the HF Trainer divides by gradient accumulation), so add the aux term unscaled
        if self.aux_loss_enabled:
            loss = loss + self.router_aux_loss_coef * aux_loss
            self._metrics[mode]["aux_loss"].append(self.accelerator.gather_for_metrics(aux_loss).mean().item())

        # Entropy
        mean_entropy = (entropies * completion_mask).sum() / completion_mask.sum().clamp(min=1.0)
        self._metrics[mode]["entropy"].append(self.accelerator.gather(mean_entropy).nanmean().item())

        # Compute the clipped probability ratios
        is_low_clipped = (coef_1 < 1 - self.epsilon_low) & (advantages < 0)
        is_high_clipped = (coef_1 > 1 + self.epsilon_high) & (advantages > 0)
        is_region_clipped = is_low_clipped | is_high_clipped
        gathered_low_clip = self.accelerator.gather(is_low_clipped.float().mean())
        self._metrics[mode]["clip_ratio/low_mean"].append(gathered_low_clip.nanmean().item())
        self._metrics[mode]["clip_ratio/low_min"].append(nanmin(gathered_low_clip).item())
        gathered_high_clip = self.accelerator.gather(is_high_clipped.float().mean())
        self._metrics[mode]["clip_ratio/high_mean"].append(gathered_high_clip.nanmean().item())
        self._metrics[mode]["clip_ratio/high_max"].append(nanmax(gathered_high_clip).item())
        gathered_clip_ratio = self.accelerator.gather(is_region_clipped.float().mean())
        self._metrics[mode]["clip_ratio/region_mean"].append(gathered_clip_ratio.nanmean().item())
        return loss

    # During eval, Trainer calls prediction_step. If no labels are present in the inputs, it only runs forward and
    # returns logits. We override prediction_step to force compute_loss, because this trainer doesn't involve labels.
    def prediction_step(self, model, inputs, prediction_loss_only, ignore_keys: list[str] | None = None):
        inputs = self._prepare_inputs(inputs)
        with torch.no_grad():
            with self.compute_loss_context_manager():
                loss = self.compute_loss(model, inputs)
            loss = loss.mean().detach()
        return loss, None, None

    def log(self, logs: dict[str, float], start_time: float | None = None) -> None:
        mode = "train" if self.model.training else "eval"
        # Average the metrics
        metrics = {}
        for key, val in self._metrics[mode].items():
            # Filter out NaN values before averaging. A reward function that returns None for all samples
            # in a batch produces NaN for that batch's metric. With logging_steps > 1, a naive sum()/len()
            # would let a single NaN contaminate valid data from other batches. Only return None when no
            # valid values remain (e.g. JSON loggers crash on float NaN).
            valid = [v for v in val if not math.isnan(v)]
            metrics[key] = sum(valid) / len(valid) if valid else None

        # This method can be called both in training and evaluation. When called in evaluation, the keys in `logs`
        # start with "eval_". We need to add the prefix "eval_" to the keys in `metrics` to match the format.
        if mode == "eval":
            metrics = {f"eval_{key}": val for key, val in metrics.items()}

        logs.update(metrics)
        super().log(logs, start_time)
        self._metrics[mode].clear()

        if self.accelerator.is_main_process and self.log_completions:
            if is_rich_available():
                print_prompt_completions_sample(
                    self._logs["prompt"],
                    self._logs["completion"],
                    self._logs["rewards"],
                    self._logs["advantages"],
                    self.state.global_step,
                    self.num_completions_to_print,
                    extra=dict(self._logs["extra"]),
                )

            logging_backends = []
            if self.args.report_to and "wandb" in self.args.report_to and wandb.run is not None:
                logging_backends.append(wandb)
            if self.args.report_to and "trackio" in self.args.report_to:
                logging_backends.append(trackio)

            table = {
                "step": [self.state.global_step] * len(self._logs["prompt"]),
                "prompt": self._logs["prompt"],
                "completion": self._logs["completion"],
                **self._logs["rewards"],
                **self._logs["extra"],
                "advantage": self._logs["advantages"],
            }

            df_base = pd.DataFrame(table)
            images_raw = self._logs["images"] or []

            for logging_backend in logging_backends:
                if images_raw:
                    images = []
                    for image_list in self._logs["images"]:
                        images.append([logging_backend.Image(image) for image in image_list])
                    df = pd.concat(
                        [df_base, pd.Series(images, name="image")],
                        axis=1,
                        copy=False,
                    )
                else:
                    df = df_base

                if self.log_unique_prompts:
                    df = df.drop_duplicates(subset=["prompt"])

                logging_backend.log({"completions": logging_backend.Table(dataframe=df)})

    # Ensure the model card is saved along with the checkpoint
    def _save_checkpoint(self, model, trial):
        if self.args.hub_model_id is None:
            model_name = Path(self.args.output_dir).name
        else:
            model_name = self.args.hub_model_id.split("/")[-1]
        self.create_model_card(model_name=model_name)
        super()._save_checkpoint(model, trial)
class UnslothRLOOTrainer(_UnslothRLOOTrainer):
    """
    
    Trainer for the Reinforce Leave One Out (RLOO) method. This algorithm was initially proposed in the paper [Back to
    Basics: Revisiting REINFORCE Style Optimization for Learning from Human Feedback in
    LLMs](https://huggingface.co/papers/2402.14740).

    Example:

    ```python
    >>> from trl import RLOOTrainer
    >>> from trl.rewards import accuracy_reward
    >>> from datasets import load_dataset

    >>> dataset = load_dataset("trl-lib/DeepMath-103K", split="train")

    >>> trainer = RLOOTrainer(
    ...     model="Qwen/Qwen2.5-0.5B-Instruct",
    ...     reward_funcs=accuracy_reward,
    ...     train_dataset=dataset,
    ... )
    >>> trainer.train()
    ```

    Args:
        model (`str` or [`~transformers.PreTrainedModel`] or [`~peft.PeftModel`]):
            Model to be trained. Can be either:

            - A string, being the *model id* of a pretrained model hosted inside a model repo on huggingface.co, or a
              path to a *directory* containing model weights saved using
              [`~transformers.PreTrainedModel.save_pretrained`], e.g., `'./my_model_directory/'`. The model is loaded
              using `<ModelArchitecture>.from_pretrained` (where `<ModelArchitecture>` is derived from the model
              config) with the keyword arguments in `args.model_init_kwargs`.
            - A [`~transformers.PreTrainedModel`] object. Only causal language models are supported.
            - A [`~peft.PeftModel`] object. Only causal language models are supported.
        reward_funcs (`RewardFunc | list[RewardFunc]`):
            Reward functions to be used for computing the rewards. To compute the rewards, we call all the reward
            functions with the prompts and completions and sum the rewards. Can be either:

            - A single reward function, such as:
                - A string: The *model ID* of a pretrained model hosted inside a model repo on huggingface.co, or a
                path to a *directory* containing model weights saved using
                [`~transformers.PreTrainedModel.save_pretrained`], e.g., `'./my_model_directory/'`. The model is loaded
                using [`~transformers.AutoModelForSequenceClassification.from_pretrained`] with `num_labels=1` and the
                keyword arguments in `args.model_init_kwargs`.
                - A [`~transformers.PreTrainedModel`] object: Only sequence classification models are supported.
                - A custom reward function: The function is provided with the prompts and the generated completions,
                  plus any additional columns in the dataset. It should return a list of rewards. Custom reward
                   functions can be either synchronous or asynchronous and can also return `None` when the reward is
                   not applicable to those samples. This is useful for multi-task training where different reward
                   functions apply to different types of samples. When a reward function returns `None` for a sample,
                   that reward function is excluded from the reward calculation for that sample. For more details, see
                   [Using a custom reward
                  function](#using-a-custom-reward-function).

                  The trainer's state is also passed to the reward function. The trainer's state is an instance of
                  [`~transformers.TrainerState`] and can be accessed by accessing the `trainer_state` argument to the
                  reward function's signature.
            - A list of reward functions, where each item can independently be any of the above types. Mixing different
            types within the list (e.g., a string model ID and a custom reward function) is allowed.
        args ([`RLOOConfig`], *optional*):
            Configuration for this trainer. If `None`, a default configuration is used.
        train_dataset ([`~datasets.Dataset`] or [`~datasets.IterableDataset`]):
            Dataset to use for training. It must include a column `"prompt"`. Any additional columns in the dataset is
            ignored. The format of the samples can be either:

            - [Standard](dataset_formats#standard): Each sample contains plain text.
            - [Conversational](dataset_formats#conversational): Each sample contains structured messages (e.g., role
              and content).
        eval_dataset ([`~datasets.Dataset`], [`~datasets.IterableDataset`] or `dict[str, Dataset | IterableDataset]`):
            Dataset to use for evaluation. It must meet the same requirements as `train_dataset`.
        processing_class ([`~transformers.PreTrainedTokenizerBase`], [`~transformers.ProcessorMixin`], *optional*):
            Processing class used to process the data. The padding side must be set to "left". If `None`, the
            processing class is loaded from the model's name with [`~transformers.AutoProcessor.from_pretrained`]. A
            padding token, `tokenizer.pad_token`, must be set. If the processing class has not set a padding token,
            `tokenizer.eos_token` will be used as the default.
        reward_processing_classes ([`~transformers.PreTrainedTokenizerBase`] or `list[PreTrainedTokenizerBase]`, *optional*):
            Processing classes corresponding to the reward functions specified in `reward_funcs`. Can be either:

            - A single processing class: Used when `reward_funcs` contains only one reward function.
            - A list of processing classes: Must match the order and length of the reward functions in `reward_funcs`.
            If set to `None`, or if an element of the list corresponding to a [`~transformers.PreTrainedModel`] is
            `None`, the tokenizer for the model is automatically loaded using
            [`~transformers.AutoTokenizer.from_pretrained`]. For elements in `reward_funcs` that are custom reward
            functions (not [`~transformers.PreTrainedModel`]), the corresponding entries in `reward_processing_classes`
            are ignored.
        callbacks (list of [`~transformers.TrainerCallback`], *optional*):
            List of callbacks to customize the training loop. Will add those to the list of default callbacks detailed
            in [here](https://huggingface.co/docs/transformers/main_classes/callback).

            If you want to remove one of the default callbacks used, use the [`~transformers.Trainer.remove_callback`]
            method.
        optimizers (`tuple[torch.optim.Optimizer | None, torch.optim.lr_scheduler.LambdaLR | None]`, *optional*, defaults to `(None, None)`):
            A tuple containing the optimizer and the scheduler to use. Will default to an instance of `AdamW` on your
            model and a scheduler given by [`~transformers.get_linear_schedule_with_warmup`] controlled by `args`.
        peft_config ([`~peft.PeftConfig`], *optional*):
            PEFT configuration used to wrap the model. If `None`, the model is not wrapped.
    
    """
    def __init__(
        self,
        model,
        reward_funcs,
        args = None,
        train_dataset = None,
        eval_dataset = None,
        processing_class = None,
        reward_processing_classes = None,
        callbacks = None,
        peft_config = None,
        **kwargs
    ):
        if args is None: args = UnslothRLOOConfig()
        use_bf16 = getattr(args, 'bf16', False)
        if type(use_bf16) is not bool: use_bf16 = False
        use_fp16 = getattr(args, 'fp16', False)
        if type(use_fp16) is not bool: use_fp16 = False
        force_float32 = False
        full_finetuning = os.environ.get('UNSLOTH_ENABLE_FULL_FINETUNING', '0') == '1'
        if not full_finetuning and (os.environ.get('UNSLOTH_FORCE_FLOAT32', '0') == '1'):
            print('Unsloth: Switching to float32 training since model cannot work with float16')
            force_float32 = True
        mixed_precision_dtype = os.environ.get('UNSLOTH_MIXED_PRECISION', 'float32')
        dtype = getattr(model.config, 'dtype', None) or getattr(model.config, 'torch_dtype', None)
        if dtype is None: dtype = model.get_input_embeddings().weight.dtype
        from unsloth_zoo.utils import _get_dtype
        dtype = _get_dtype(dtype)
        float16 = dtype == torch.float16
        if not force_float32 and (float16 and use_bf16): raise TypeError('Unsloth: Model is in float16 precision but you want to use bfloat16 precision. Set fp16 to `True` and bf16 to `False`')
        if not force_float32 and (not float16 and use_fp16): raise TypeError('Unsloth: Model is in bfloat16 precision but you want to use float16 precision. Set fp16 to `False` and bf16 to `True`')
        if force_float32:
            # Forced float32 training
            args.fp16 = False
            args.bf16 = False
            os.environ['ACCELERATE_MIXED_PRECISION'] = 'no'
            if hasattr(args, 'mixed_precision'): args.mixed_precision = 'no'
            # args.mixed_precision is a new argument which needs to be set now
        elif (not use_bf16 and not use_fp16) and mixed_precision_dtype == 'float32':
            # Mixed precision training
            args.fp16 = float16
            args.bf16 = not float16
            os.environ['ACCELERATE_MIXED_PRECISION'] = 'fp16' if float16 else 'bf16'
            if hasattr(args, 'mixed_precision'): args.mixed_precision = 'fp16' if float16 else 'bf16'
            # args.mixed_precision is a new argument which needs to be set now
        elif mixed_precision_dtype == 'bfloat16':
            # Both False since bfloat16 full finetuning doesn't do any autocasting.
            args.fp16 = False
            args.bf16 = False
            os.environ['ACCELERATE_MIXED_PRECISION'] = 'no'
            if hasattr(args, 'mixed_precision'): args.mixed_precision = 'no'
            # args.mixed_precision is a new argument which needs to be set now
        
        if getattr(args, 'eval_dataset', None) is not None and getattr(args, 'eval_strategy', 'no') == 'no':
            args.eval_strategy = 'steps'
            if getattr(args, 'eval_steps', None) is None: args.eval_steps = 0.1
        ga_steps = getattr(args, 'gradient_accumulation_steps', None)
        if ga_steps is not None and ga_steps > 1:
            from transformers import __version__ as transformers_version
            if Version(transformers_version) <= Version('4.45.2'):
                print('**** Unsloth: Please use our fixed gradient_accumulation_steps by updating transformers, TRL and Unsloth!\n'
                      '`pip install --upgrade --no-cache-dir --force-reinstall --no-deps unsloth transformers trl unsloth_zoo`')
        if getattr(args, 'eval_strategy', 'no') != 'no':
            eval_bsz = getattr(args, 'per_device_eval_batch_size', 8)
            if eval_bsz == 8 and args.per_device_train_batch_size < eval_bsz: args.per_device_eval_batch_size = args.per_device_train_batch_size
            if getattr(args, 'eval_accumulation_steps', None) is None and ga_steps is not None: args.eval_accumulation_steps = ga_steps
        fp16_full_eval = getattr(args, 'fp16_full_eval', False)
        if type(fp16_full_eval) is not bool: fp16_full_eval = False
        bf16_full_eval = getattr(args, 'bf16_full_eval', False)
        if type(bf16_full_eval) is not bool: bf16_full_eval = False
        if args.fp16 and bf16_full_eval: args.bf16_full_eval = False; args.fp16_full_eval = True
        if args.bf16 and fp16_full_eval: args.bf16_full_eval = True; args.fp16_full_eval = False
        if force_float32:
            args.bf16_full_eval = False
            args.fp16_full_eval = False
        elif os.environ.get('UNSLOTH_MIXED_PRECISION', 'float32') == 'bfloat16':
            args.bf16_full_eval = True
            args.fp16_full_eval = False
        elif not bf16_full_eval and not fp16_full_eval:
            args.bf16_full_eval = args.bf16
            args.fp16_full_eval = args.fp16
        _output_logits = False
        if locals().get('compute_metrics', None) is not None: _output_logits = True
        if locals().get('preprocess_logits_for_metrics', None) is not None: _output_logits = True
        if _output_logits:
            os.environ['UNSLOTH_RETURN_LOGITS'] = '1'
        if model is not None:
            _warnings_issued = getattr(model, 'warnings_issued', None)
            if _warnings_issued is None:
                model.warnings_issued = {}
            elif not isinstance(_warnings_issued, dict):
                try:
                    model.warnings_issued = dict(_warnings_issued)
                except Exception:
                    model.warnings_issued = {}
        if 'max_seq_length' not in locals() and not hasattr(args, 'max_seq_length'):
            pass
        else:
            model_max_seq_length = getattr(model, 'max_seq_length', None)
            args_max_seq_length  = getattr(args,  'max_seq_length', None)
            if args_max_seq_length is None and model_max_seq_length is not None:
                max_seq_length = model.max_seq_length
                if hasattr(args, 'max_seq_length'): args.max_seq_length = max_seq_length
            elif args_max_seq_length is not None and model_max_seq_length is not None:
                if args_max_seq_length > model_max_seq_length:
                    print('Unsloth: You set `max_seq_length` as ' + str(args_max_seq_length) + ' but '
                           'the maximum the model supports is ' + str(model_max_seq_length) + '. We shall reduce it.')
                    args.max_seq_length = model_max_seq_length
        if model is not None and hasattr(model, 'for_training'):
            model.for_training(use_gradient_checkpointing=getattr(args, 'gradient_checkpointing', True))
        if 'tokenizer' in locals() and hasattr(tokenizer, 'padding_side'): tokenizer.padding_side = 'right'
        if 'processing_class' in locals():
            if hasattr(processing_class, 'padding_side'): processing_class.padding_side = 'right'
            if hasattr(processing_class, 'tokenizer') and hasattr(processing_class.tokenizer, 'padding_side'): processing_class.tokenizer.padding_side = 'right'
        other_metrics = []
        
        from unsloth_zoo.logging_utils import PatchRLStatistics
        PatchRLStatistics('rloo_trainer', other_metrics)
        
        # [TODO] Fix up DataParallel multiplying batch sizes
        # [TODO] DDP works, but DP seems to not work? [TODO]
        if getattr(args, "parallel_mode", None) == ParallelMode.NOT_DISTRIBUTED and args.n_gpu > 1:
            if getattr(args, "_n_gpu", 1) != 1:
                args._n_gpu = 1
        if "model" in locals() and hasattr(model, "for_training"):
            model.for_training(use_gradient_checkpointing=getattr(args, 'gradient_checkpointing', True))
        super().__init__(
            model = model,
            reward_funcs = reward_funcs,
            args = args,
            train_dataset = train_dataset,
            eval_dataset = eval_dataset,
            processing_class = processing_class,
            reward_processing_classes = reward_processing_classes,
            callbacks = callbacks,
            peft_config = peft_config,**kwargs)
        if "model" in locals() and hasattr(model, "for_inference"):
            model.for_inference()
        if hasattr(self, 'neftune_hook_handle'):
            self.neftune_hook_handle.remove()
            if hasattr(self, 'neftune_hook_handle'): del self.neftune_hook_handle
        if getattr(args, 'neftune_noise_alpha', None) is not None:
            model.get_input_embeddings().neftune_noise_alpha = self.neftune_noise_alpha
        pass
        if hasattr(self, 'accelerator'):
            scaler = self.accelerator.scaler
            current_model = model
            while hasattr(current_model, 'model'):
                current_model.accelerator_scaler = scaler
                current_model = current_model.model
            current_model.accelerator_scaler = scaler
        pass
        if hasattr(self, 'train'):
            self.train = MethodType(prepare_for_training_mode(self.__class__.train), self)
        pass
        if hasattr(self, 'llm') and self.llm is not None and hasattr(self.llm, 'get_tokenizer'):
            _vllm_tok = self.llm.get_tokenizer()
            _pc = getattr(self, 'processing_class', None) or getattr(self, 'tokenizer', None)
            if _vllm_tok is not None and _pc is not None and getattr(_pc, 'chat_template', None) is not None and getattr(_vllm_tok, 'chat_template', None) is None:
                _vllm_tok.chat_template = _pc.chat_template
        pass
        
pass


if hasattr(logger, "addFilter"):
    import logging
    class HideLoggingMessage(logging.Filter):
        def __init__(self, text): self.text = text
        def filter(self, x): return not (self.text in x.getMessage())
    pass
    logger.addFilter(HideLoggingMessage("`use_cache=True`"))