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	# coding=utf-8
	# Copyright 2020 The Google AI Language Team Authors, Facebook AI Research authors and The HuggingFace Inc. team.
	# Copyright (c) 2020, NVIDIA CORPORATION. All rights reserved.
	#
	# Licensed under the Apache License, Version 2.0 (the "License");
	# you may not use this file except in compliance with the License.
	# You may obtain a copy of the License at
	#
	# http://www.apache.org/licenses/LICENSE-2.0
	#
	# Unless required by applicable law or agreed to in writing, software
	# distributed under the License is distributed on an "AS IS" BASIS,
	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	# See the License for the specific language governing permissions and
	# limitations under the License.
	import copy
	import inspect
	import os
	import warnings
	from dataclasses import dataclass
	from typing import TYPE_CHECKING, Any, Callable, Optional, Union

	import torch
	import torch.distributed as dist
	from packaging import version
	from torch import nn

	from ..cache_utils import (
	Cache,
	DynamicCache,
	EncoderDecoderCache,
	QuantizedCache,
	StaticCache,
	)
	from ..dynamic_module_utils import (
	check_python_requirements,
	get_cached_module_file,
	get_class_in_module,
	resolve_trust_remote_code,
	)
	from ..integrations.deepspeed import is_deepspeed_zero3_enabled
	from ..integrations.fsdp import is_fsdp_managed_module
	from ..masking_utils import create_masks_for_generate
	from ..pytorch_utils import isin_mps_friendly
	from ..tokenization_utils import ExtensionsTrie
	from ..utils import (
	ModelOutput,
	TransformersKwargs,
	is_accelerate_available,
	is_hqq_available,
	is_optimum_quanto_available,
	is_torchdynamo_exporting,
	logging,
	)
	from .candidate_generator import (
	AssistantVocabTranslatorCache,
	AssistedCandidateGenerator,
	AssistedCandidateGeneratorDifferentTokenizers,
	CandidateGenerator,
	EarlyExitCandidateGenerator,
	PromptLookupCandidateGenerator,
	UniversalSpeculativeDecodingGenerator,
	_prepare_attention_mask,
	_prepare_token_type_ids,
	)
	from .configuration_utils import (
	ALL_STATIC_CACHE_IMPLEMENTATIONS,
	DEPRECATED_STATIC_CACHE_IMPLEMENTATIONS,
	STATIC_CACHE_IMPLEMENTATIONS,
	GenerationConfig,
	GenerationMode,
	)
	from .continuous_batching import ContinuousMixin
	from .logits_process import (
	EncoderNoRepeatNGramLogitsProcessor,
	EncoderRepetitionPenaltyLogitsProcessor,
	EpsilonLogitsWarper,
	EtaLogitsWarper,
	ExponentialDecayLengthPenalty,
	ForcedBOSTokenLogitsProcessor,
	ForcedEOSTokenLogitsProcessor,
	InfNanRemoveLogitsProcessor,
	LogitNormalization,
	LogitsProcessorList,
	MinLengthLogitsProcessor,
	MinNewTokensLengthLogitsProcessor,
	MinPLogitsWarper,
	NoBadWordsLogitsProcessor,
	NoRepeatNGramLogitsProcessor,
	PrefixConstrainedLogitsProcessor,
	RepetitionPenaltyLogitsProcessor,
	SequenceBiasLogitsProcessor,
	SuppressTokensAtBeginLogitsProcessor,
	SuppressTokensLogitsProcessor,
	TemperatureLogitsWarper,
	TopKLogitsWarper,
	TopPLogitsWarper,
	TypicalLogitsWarper,
	UnbatchedClassifierFreeGuidanceLogitsProcessor,
	)
	from .stopping_criteria import (
	ConfidenceCriteria,
	EosTokenCriteria,
	MaxLengthCriteria,
	MaxTimeCriteria,
	StoppingCriteria,
	StoppingCriteriaList,
	StopStringCriteria,
	)


	if TYPE_CHECKING:
	from ..modeling_utils import PreTrainedModel
	from ..tokenization_utils_base import PreTrainedTokenizerBase
	from .streamers import BaseStreamer

	logger = logging.get_logger(__name__)

	if is_accelerate_available():
	from accelerate.hooks import AlignDevicesHook, add_hook_to_module


	# Variable names used to hold the cache at generation time
	ALL_CACHE_NAMES = [
	"past_key_values", # default
	"cache_params", # mamba-based models
	"state", # rwkv
	"mems", # xlnet
	"past_buckets_states", # reformer
	]

	GENERATION_MODES_MAPPING = {
	GenerationMode.SAMPLE: "_sample",
	GenerationMode.GREEDY_SEARCH: "_sample",
	GenerationMode.BEAM_SEARCH: "_beam_search",
	GenerationMode.BEAM_SAMPLE: "_beam_search",
	GenerationMode.ASSISTED_GENERATION: "_assisted_decoding",
	# Deprecated methods
	GenerationMode.DOLA_GENERATION: "transformers-community/dola",
	GenerationMode.CONTRASTIVE_SEARCH: "transformers-community/contrastive-search",
	GenerationMode.GROUP_BEAM_SEARCH: "transformers-community/group-beam-search",
	GenerationMode.CONSTRAINED_BEAM_SEARCH: "transformers-community/constrained-beam-search",
	}


	@dataclass
	class GenerateDecoderOnlyOutput(ModelOutput):
	"""
	Outputs of decoder-only generation models, when using non-beam methods.

	Args:
	sequences (`torch.LongTensor` of shape `(batch_size, sequence_length)`):
	The generated sequences. The second dimension (sequence_length) is either equal to `max_length` or shorter
	if all batches finished early due to the `eos_token_id`.
	scores (`tuple(torch.FloatTensor)` optional, returned when `output_scores=True`):
	Processed prediction scores of the language modeling head (scores for each vocabulary token before SoftMax)
	at each generation step. Tuple of `torch.FloatTensor` with up to `max_new_tokens` elements (one element for
	each generated token), with each tensor of shape `(batch_size, config.vocab_size)`.
	logits (`tuple(torch.FloatTensor)` optional, returned when `output_logits=True`):
	Unprocessed prediction scores of the language modeling head (scores for each vocabulary token before SoftMax)
	at each generation step. Tuple of `torch.FloatTensor` with up to `max_new_tokens` elements (one element for
	each generated token), with each tensor of shape `(batch_size, config.vocab_size)`.
	attentions (`tuple(tuple(torch.FloatTensor))`, optional, returned when `output_attentions=True`):
	Tuple (one element for each generated token) of tuples (one element for each layer of the decoder) of
	`torch.FloatTensor` of shape `(batch_size, num_heads, generated_length, sequence_length)`.
	hidden_states (`tuple(tuple(torch.FloatTensor))`, optional, returned when `output_hidden_states=True`):
	Tuple (one element for each generated token) of tuples (one element for each layer of the decoder) of
	`torch.FloatTensor` of shape `(batch_size, generated_length, hidden_size)`.
	past_key_values (`Cache`, optional, returned when `use_cache=True`):
	Returns the model cache, used to speed up decoding. Different models have a different cache format, check
	the model's documentation. Usually, a [`~cache_utils.Cache`] instance.
	"""

	sequences: torch.LongTensor
	scores: Optional[tuple[torch.FloatTensor]] = None
	logits: Optional[tuple[torch.FloatTensor]] = None
	attentions: Optional[tuple[tuple[torch.FloatTensor]]] = None
	hidden_states: Optional[tuple[tuple[torch.FloatTensor]]] = None
	past_key_values: Optional[Cache] = None


	@dataclass
	class GenerateEncoderDecoderOutput(ModelOutput):
	"""
	Outputs of encoder-decoder generation models, when using non-beam methods.

	Args:
	sequences (`torch.LongTensor` of shape `(batch_size*num_return_sequences, sequence_length)`):
	The generated sequences. The second dimension (sequence_length) is either equal to `max_length` or shorter
	if all batches finished early due to the `eos_token_id`.
	scores (`tuple(torch.FloatTensor)` optional, returned when `output_scores=True`):
	Processed prediction scores of the language modeling head (scores for each vocabulary token before SoftMax)
	at each generation step. Tuple of `torch.FloatTensor` with up to `max_new_tokens` elements (one element for
	each generated token), with each tensor of shape `(batch_size, config.vocab_size)`.
	logits (`tuple(torch.FloatTensor)` optional, returned when `output_logits=True`):
	Unprocessed prediction scores of the language modeling head (scores for each vocabulary token before SoftMax)
	at each generation step. Tuple of `torch.FloatTensor` with up to `max_new_tokens` elements (one element for
	each generated token), with each tensor of shape `(batch_size, config.vocab_size)`.
	encoder_attentions (`tuple(torch.FloatTensor)`, optional, returned when `output_attentions=True`):
	Tuple of `torch.FloatTensor` (one for each layer of the decoder) of shape `(batch_size, num_heads,
	sequence_length, sequence_length)`.
	encoder_hidden_states (`tuple(torch.FloatTensor)`, optional, returned when `output_hidden_states=True`):
	Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of
	shape `(batch_size, sequence_length, hidden_size)`.
	decoder_attentions (`tuple(tuple(torch.FloatTensor))`, optional, returned when `output_attentions=True`):
	Tuple (one element for each generated token) of tuples (one element for each layer of the decoder) of
	`torch.FloatTensor` of shape `(batch_size, num_heads, generated_length, sequence_length)`.
	cross_attentions (`tuple(tuple(torch.FloatTensor))`, optional, returned when `output_attentions=True`):
	Tuple (one element for each generated token) of tuples (one element for each layer of the decoder) of
	`torch.FloatTensor` of shape `(batch_size, num_heads, generated_length, sequence_length)`.
	decoder_hidden_states (`tuple(tuple(torch.FloatTensor))`, optional, returned when `output_hidden_states=True`):
	Tuple (one element for each generated token) of tuples (one element for each layer of the decoder) of
	`torch.FloatTensor` of shape `(batch_size, generated_length, hidden_size)`.
	past_key_values (`Cache`, optional, returned when `use_cache=True`):
	Returns the model cache, used to speed up decoding. Different models have a different cache format, check
	the model's documentation. Usually, a [`~cache_utils.Cache`] instance.
	"""

	sequences: torch.LongTensor
	scores: Optional[tuple[torch.FloatTensor]] = None
	logits: Optional[tuple[torch.FloatTensor]] = None
	encoder_attentions: Optional[tuple[torch.FloatTensor]] = None
	encoder_hidden_states: Optional[tuple[torch.FloatTensor]] = None
	decoder_attentions: Optional[tuple[tuple[torch.FloatTensor]]] = None
	cross_attentions: Optional[tuple[tuple[torch.FloatTensor]]] = None
	decoder_hidden_states: Optional[tuple[tuple[torch.FloatTensor]]] = None
	past_key_values: Optional[Cache] = None


	@dataclass
	class GenerateBeamDecoderOnlyOutput(ModelOutput):
	"""
	Outputs of decoder-only generation models, when using beam methods.

	Args:
	sequences (`torch.LongTensor` of shape `(batch_size*num_return_sequences, sequence_length)`):
	The generated sequences. The second dimension (sequence_length) is either equal to `max_length` or shorter
	if all batches finished early due to the `eos_token_id`.
	sequences_scores (`torch.FloatTensor` of shape `(batch_sizenum_return_sequences)`, optional*, returned when `output_scores=True`):
	Final beam scores of the generated `sequences`.
	scores (`tuple(torch.FloatTensor)` optional, returned when `output_scores=True`):
	Beam transition scores for each vocabulary token at each generation step. Beam transition scores consisting
	of log probabilities of tokens conditioned on log softmax of previously generated tokens in this beam.
	Tuple of `torch.FloatTensor` with up to `max_new_tokens` elements (one element for each generated token),
	with each tensor of shape `(batch_size*num_beams, config.vocab_size)`.
	logits (`tuple(torch.FloatTensor)` optional, returned when `output_logits=True`):
	Unprocessed prediction scores of the language modeling head (scores for each vocabulary token before SoftMax)
	at each generation step. Tuple of `torch.FloatTensor` with up to `max_new_tokens` elements (one element for
	each generated token), with each tensor of shape `(batch_size*num_beams, config.vocab_size)`.
	beam_indices (`torch.LongTensor`, optional, returned when `output_scores=True`):
	Beam indices of generated token id at each generation step. `torch.LongTensor` of shape
	`(batch_size*num_return_sequences, sequence_length)`.
	attentions (`tuple(tuple(torch.FloatTensor))`, optional, returned when `output_attentions=True`):
	Tuple (one element for each generated token) of tuples (one element for each layer of the decoder) of
	`torch.FloatTensor` of shape `(batch_size*num_beams, num_heads, generated_length, sequence_length)`.
	hidden_states (`tuple(tuple(torch.FloatTensor))`, optional, returned when `output_hidden_states=True`):
	Tuple (one element for each generated token) of tuples (one element for each layer of the decoder) of
	`torch.FloatTensor` of shape `(batch_sizenum_beamsnum_return_sequences, generated_length, hidden_size)`.
	past_key_values (`Cache`, optional, returned when `use_cache=True`):
	Returns the model cache, used to speed up decoding. Different models have a different cache format, check
	the model's documentation. Usually, a [`~cache_utils.Cache`] instance.
	"""

	sequences: torch.LongTensor
	sequences_scores: Optional[torch.FloatTensor] = None
	scores: Optional[tuple[torch.FloatTensor]] = None
	logits: Optional[tuple[torch.FloatTensor]] = None
	beam_indices: Optional[torch.LongTensor] = None
	attentions: Optional[tuple[tuple[torch.FloatTensor]]] = None
	hidden_states: Optional[tuple[tuple[torch.FloatTensor]]] = None
	past_key_values: Optional[Cache] = None


	@dataclass
	class GenerateBeamEncoderDecoderOutput(ModelOutput):
	"""
	Outputs of encoder-decoder generation models, when using beam methods.

	Args:
	sequences (`torch.LongTensor` of shape `(batch_size*num_return_sequences, sequence_length)`):
	The generated sequences. The second dimension (sequence_length) is either equal to `max_length` or shorter
	if all batches finished early due to the `eos_token_id`.
	sequences_scores (`torch.FloatTensor` of shape `(batch_sizenum_return_sequences)`, optional*, returned when `output_scores=True`):
	Final beam scores of the generated `sequences`.
	scores (`tuple(torch.FloatTensor)` optional, returned when `output_scores=True`):
	Beam transition scores for each vocabulary token at each generation step. Beam transition scores consisting
	of log probabilities of tokens conditioned on log softmax of previously generated tokens in this beam.
	Tuple of `torch.FloatTensor` with up to `max_new_tokens` elements (one element for each generated token),
	with each tensor of shape `(batch_size*num_beams, config.vocab_size)`.
	logits (`tuple(torch.FloatTensor)` optional, returned when `output_logits=True`):
	Unprocessed prediction scores of the language modeling head (scores for each vocabulary token before SoftMax)
	at each generation step. Tuple of `torch.FloatTensor` with up to `max_new_tokens` elements (one element for
	each generated token), with each tensor of shape `(batch_size*num_beams, config.vocab_size)`.
	beam_indices (`torch.LongTensor`, optional, returned when `output_scores=True`):
	Beam indices of generated token id at each generation step. `torch.LongTensor` of shape
	`(batch_size*num_return_sequences, sequence_length)`.
	encoder_attentions (`tuple(torch.FloatTensor)`, optional, returned when `output_attentions=True`):
	Tuple of `torch.FloatTensor` (one for each layer of the decoder) of shape `(batch_size, num_heads,
	sequence_length, sequence_length)`.
	encoder_hidden_states (`tuple(torch.FloatTensor)`, optional, returned when `output_hidden_states=True`):
	Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of
	shape `(batch_sizenum_beamsnum_return_sequences, sequence_length, hidden_size)`.
	decoder_attentions (`tuple(tuple(torch.FloatTensor))`, optional, returned when `output_attentions=True`):
	Tuple (one element for each generated token) of tuples (one element for each layer of the decoder) of
	`torch.FloatTensor` of shape `(batch_sizenum_beamsnum_return_sequences, num_heads, generated_length,
	sequence_length)`.
	cross_attentions (`tuple(tuple(torch.FloatTensor))`, optional, returned when `output_attentions=True`):
	Tuple (one element for each generated token) of tuples (one element for each layer of the decoder) of
	`torch.FloatTensor` of shape `(batch_size, num_heads, generated_length, sequence_length)`.
	decoder_hidden_states (`tuple(tuple(torch.FloatTensor))`, optional, returned when `output_hidden_states=True`):
	Tuple (one element for each generated token) of tuples (one element for each layer of the decoder) of
	`torch.FloatTensor` of shape `(batch_sizenum_beamsnum_return_sequences, generated_length, hidden_size)`.
	past_key_values (`Cache`, optional, returned when `use_cache=True`):
	Returns the model cache, used to speed up decoding. Different models have a different cache format, check
	the model's documentation. Usually, a [`~cache_utils.Cache`] instance.
	"""

	sequences: torch.LongTensor
	sequences_scores: Optional[torch.FloatTensor] = None
	scores: Optional[tuple[torch.FloatTensor]] = None
	logits: Optional[tuple[torch.FloatTensor]] = None
	beam_indices: Optional[torch.LongTensor] = None
	encoder_attentions: Optional[tuple[torch.FloatTensor]] = None
	encoder_hidden_states: Optional[tuple[torch.FloatTensor]] = None
	decoder_attentions: Optional[tuple[tuple[torch.FloatTensor]]] = None
	cross_attentions: Optional[tuple[tuple[torch.FloatTensor]]] = None
	decoder_hidden_states: Optional[tuple[tuple[torch.FloatTensor]]] = None
	past_key_values: Optional[Cache] = None


	# TODO (joao): remove the equivalent classes and typing shortcuts below in v5
	# Equivalent classes (kept for retrocompatibility purposes)
	GreedySearchDecoderOnlyOutput = GenerateDecoderOnlyOutput
	ContrastiveSearchDecoderOnlyOutput = GenerateDecoderOnlyOutput
	SampleDecoderOnlyOutput = GenerateDecoderOnlyOutput

	ContrastiveSearchEncoderDecoderOutput = GenerateEncoderDecoderOutput
	GreedySearchEncoderDecoderOutput = GenerateEncoderDecoderOutput
	SampleEncoderDecoderOutput = GenerateEncoderDecoderOutput

	BeamSearchDecoderOnlyOutput = GenerateBeamDecoderOnlyOutput
	BeamSampleDecoderOnlyOutput = GenerateBeamDecoderOnlyOutput

	BeamSearchEncoderDecoderOutput = GenerateBeamEncoderDecoderOutput
	BeamSampleEncoderDecoderOutput = GenerateBeamEncoderDecoderOutput

	GreedySearchOutput = Union[GreedySearchEncoderDecoderOutput, GreedySearchDecoderOnlyOutput]
	SampleOutput = Union[SampleEncoderDecoderOutput, SampleDecoderOnlyOutput]
	BeamSearchOutput = Union[BeamSearchEncoderDecoderOutput, BeamSearchDecoderOnlyOutput]
	BeamSampleOutput = Union[BeamSampleEncoderDecoderOutput, BeamSampleDecoderOnlyOutput]
	ContrastiveSearchOutput = Union[ContrastiveSearchEncoderDecoderOutput, ContrastiveSearchDecoderOnlyOutput]

	# Typing shortcuts
	GenerateNonBeamOutput = Union[GenerateDecoderOnlyOutput, GenerateEncoderDecoderOutput]
	GenerateBeamOutput = Union[GenerateBeamDecoderOnlyOutput, GenerateBeamEncoderDecoderOutput]
	GenerateOutput = Union[GenerateNonBeamOutput, GenerateBeamOutput]


	class GenerationMixin(ContinuousMixin):
	"""
	A class containing all functions for auto-regressive text generation, to be used as a mixin in model classes.
	Inheriting from this class causes the model to have special generation-related behavior, such as loading a
	`GenerationConfig` at initialization time or ensuring `generate`-related tests are run in `transformers` CI.

	A model class should inherit from `GenerationMixin` to enable calling methods like `generate`, or when it
	has defined a custom `generate` method that relies on `GenerationMixin`, directly or indirectly, which
	approximately shares the same interface to public methods like `generate`. Three examples:
	- `LlamaForCausalLM` should inherit from `GenerationMixin` to enable calling `generate` and other public
	methods in the mixin;
	- `BlipForQuestionAnswering` has a custom `generate` method that approximately shares the same interface as
	`GenerationMixin.generate` (it has a few extra arguments, and the same output). That function also calls
	`GenerationMixin.generate` indirectly, through an inner model. As such, `BlipForQuestionAnswering` should
	inherit from `GenerationMixin` to benefit from all generation-related automation in our codebase;
	- `BarkModel` has a custom `generate` method and one of its inner models calls `GenerationMixin.generate`.
	However, its `generate` does not share the same interface as `GenerationMixin.generate`. In this case,
	`BarkModel` should NOT inherit from `GenerationMixin`, as it breaks the `generate` interface.

	The class exposes [`~generation.GenerationMixin.generate`], which can be used for:
	- greedy decoding if `num_beams=1` and `do_sample=False`
	- multinomial sampling if `num_beams=1` and `do_sample=True`
	- beam-search decoding if `num_beams>1` and `do_sample=False`
	- beam-search multinomial sampling if `num_beams>1` and `do_sample=True`
	- assisted decoding if `assistant_model` or `prompt_lookup_num_tokens` is passed to `.generate()`

	To learn more about decoding strategies refer to the [text generation strategies guide](../generation_strategies).
	"""

	def load_custom_generate(
	self,
	pretrained_model_name_or_path: Optional[Union[str, os.PathLike]] = None,
	trust_remote_code: Optional[bool] = None,
	**kwargs,
	) -> Callable:
	"""
	Loads and returns a custom generate function, given a model repo.

	Args:
	pretrained_model_name_or_path (`str` or `os.PathLike`):
	Can be either:
	- A string, the model id of a pretrained model hosted inside a model repo on huggingface.co.
	- A path to a directory containing model weights saved using
	[`~PreTrainedModel.save_pretrained`], e.g., `./my_model_directory/`.
	trust_remote_code (`bool`, optional):
	Whether or not to allow for custom models defined on the Hub in their own modeling files. This option
	should only be set to `True` for repositories you trust and in which you have read the code, as it will
	execute code present on the Hub on your local machine.
	**kwargs:
	Additional keyword arguments for remote code loading.

	Raises:
	OSError: If `pretrained_model_name_or_path` does not contain a `custom_generate` subdirectory.

	Returns:
	A callable that can be used to generate text.
	"""
	# Fetches the generate.py file from the model repo. If it doesn't exist, a file in `.no_exist` cache directory
	# is created (preventing future hub requests), and an OSError is raised.
	try:
	module = get_cached_module_file(
	pretrained_model_name_or_path, module_file="custom_generate/generate.py", **kwargs
	)
	except OSError:
	raise OSError(
	f"`{pretrained_model_name_or_path}` does not contain a `custom_generate` subdirectory with a "
	"`generate.py` file, can't load the custom generate function."
	)

	# Handle opt-in `trust_remote_code` and related exceptions
	is_local_code = os.path.exists(pretrained_model_name_or_path)
	error_message = (
	f"The repository `{pretrained_model_name_or_path}` contains custom generation code that will override "
	"the default `generate` method."
	)
	resolve_trust_remote_code(
	trust_remote_code,
	pretrained_model_name_or_path,
	has_local_code=is_local_code,
	has_remote_code=not is_local_code,
	error_message=error_message,
	)

	# Load the custom generate function
	check_python_requirements(
	pretrained_model_name_or_path, requirements_file="custom_generate/requirements.txt", **kwargs
	)
	custom_generate_function = get_class_in_module("generate", module)
	return custom_generate_function

	def _cache_dependant_input_preparation(
	self,
	input_ids: torch.LongTensor,
	inputs_embeds: Optional[torch.FloatTensor],
	cache_position: Optional[torch.LongTensor],
	) -> tuple[torch.FloatTensor, torch.LongTensor]:
	"""
	Generic cache-dependent input preparation
	The code is put in a separate function to allow granular unit testing
	as it needs a different implementation to be exportable.

	If we have cache: let's slice `input_ids` through `cache_position`, to keep only the unprocessed tokens
	- Exception 1: when passing input_embeds, input_ids may be missing entries
	- Exception 2: some generation methods do special slicing of input_ids, so we don't need to do it here
	- Exception 3: with synced GPUs cache_position may go out of bounds, but we only want dummy token in that case.
	- Exception 4: If input_embeds are passed then slice it through `cache_position`, to keep only the unprocessed tokens and
	generate the first token for each sequence. Later use the generated Input ids for continuation.

	The current implementation does not rely on ``self`` and could be
	a class method. It is left as a standard method to be easily rewritten.
	"""
	if is_torchdynamo_exporting():
	return self._cache_dependant_input_preparation_exporting(input_ids, inputs_embeds, cache_position)
	if inputs_embeds is not None and input_ids.shape[1] == 0: # Exception 4
	inputs_embeds = inputs_embeds[:, -cache_position.shape[0] :]
	elif (
	inputs_embeds is not None # Exception 1
	or (cache_position[-1] >= input_ids.shape[1]) # Exception 3
	):
	input_ids = input_ids[:, -cache_position.shape[0] :]
	elif input_ids.shape[1] != cache_position.shape[0]: # Default case (the "else", a no op, is Exception 2)
	input_ids = input_ids[:, cache_position]
	return inputs_embeds, input_ids

	def _cache_dependant_input_preparation_exporting(
	self,
	input_ids: torch.LongTensor,
	inputs_embeds: Optional[torch.FloatTensor],
	cache_position: Optional[torch.LongTensor],
	) -> tuple[torch.FloatTensor, torch.LongTensor]:
	"""
	This method implements method ``_cache_dependant_input_preparation``
	with :func:`torch.cond` to make it exportable with :func:`torch.export.export`.
	The code is put in a separate function to allow granular unit testing.
	"""
	if inputs_embeds is None:
	input_ids = input_ids[:, cache_position]
	else:
	# This is the code we need to implemented with torch.cond.
	# if input_ids.shape[1] == 0:
	# inputs_embeds = inputs_embeds[:, -cache_position.shape[0] :]
	# else:
	# if cache_position[-1] >= input_ids.shape[1]:
	# input_ids = input_ids[:, -cache_position.shape[0] :]
	# else:
	# if input_ids.shape[1] != cache_position.shape[0]:
	# input_ids = input_ids[:, cache_position]
	# We need to clone the outputs to avoid aliasing.
	def branch_1(inputs_embeds, cache_position):
	return inputs_embeds[:, -cache_position.shape[0] :].clone()

	def branch_2(input_ids, cache_position):
	return input_ids[:, -cache_position.shape[0] :].clone()

	def branch_3(input_ids, cache_position):
	return input_ids[:, cache_position].clone()

	inputs_embeds, input_ids = torch.cond(
	input_ids.shape[1] == 0,
	(
	lambda input_ids, inputs_embeds, cache_position: (
	branch_1(inputs_embeds, cache_position),
	input_ids.clone(),
	)
	),
	(
	lambda input_ids, inputs_embeds, cache_position: (
	inputs_embeds,
	torch.cond(
	cache_position[-1] >= input_ids.shape[1],
	branch_2,
	lambda input_ids, cache_position: (
	torch.cond(
	input_ids.shape[1] != cache_position.shape[0],
	branch_3,
	(lambda input_ids, cache_position: input_ids.clone()),
	[input_ids, cache_position],
	)
	),
	[input_ids, cache_position],
	),
	)
	),
	[input_ids, inputs_embeds, cache_position],
	)
	return inputs_embeds, input_ids

	def prepare_inputs_for_generation(
	self,
	input_ids: torch.LongTensor,
	past_key_values: Optional[Cache] = None,
	attention_mask: Optional[torch.LongTensor] = None,
	inputs_embeds: Optional[torch.FloatTensor] = None,
	cache_position: Optional[torch.LongTensor] = None,
	**kwargs,
	):
	"""
	Prepare the model inputs for generation. Notable steps include selecting the correct input key and cloning when appropriate,
	creating position_ids from the attention_mask when missing, slicing inputs and converting 2D attention masks to 4D for
	compilable caches, and finally forwarding all additional keyword arguments unchanged to the model's forward pass.

	See the forward pass in the model documentation for expected arguments (different models might have different
	requirements for e.g. `past_key_values`). This function should work as is for most LLMs.
	"""

	# 1. Handle BC:
	model_inputs = {}
	model_inputs["cache_position"] = cache_position

	# 2. Generic cache-dependent input preparation
	if past_key_values is not None:
	model_inputs["past_key_values"] = past_key_values
	# TODO (joao): handle the case where cache length == input_ids length. The function below results in an
	# exception because we get empty input_ids after slicing. In essence, we need to roll back the cache 1
	# token to recompute the logits for the first token to be generated (but not all caches support roll backs)
	inputs_embeds, input_ids = self._cache_dependant_input_preparation(
	input_ids, inputs_embeds, cache_position
	)

	# 3. Prepare base model inputs
	input_ids_key = "decoder_input_ids" if self.config.is_encoder_decoder else "input_ids"
	# if `inputs_embeds` are passed, we only want to use them in the 1st generation step for every prompt.
	if not self.config.is_encoder_decoder:
	if inputs_embeds is not None and len(cache_position) == inputs_embeds.shape[1]:
	model_inputs[input_ids_key] = None
	model_inputs["inputs_embeds"] = inputs_embeds
	else:
	# `clone` calls in this function ensure a consistent stride. See #32227
	model_inputs[input_ids_key] = input_ids.clone(memory_format=torch.contiguous_format)
	model_inputs["inputs_embeds"] = None
	else:
	model_inputs[input_ids_key] = input_ids.clone(memory_format=torch.contiguous_format)

	# 4. Create missing `position_ids` on the fly
	encoder_attention_mask = attention_mask if self.config.is_encoder_decoder else None
	attention_mask = (
	kwargs.pop("decoder_attention_mask", None) if self.config.is_encoder_decoder else attention_mask
	)
	attention_mask_key = "decoder_attention_mask" if self.config.is_encoder_decoder else "attention_mask"
	position_ids_key = "decoder_position_ids" if self.config.is_encoder_decoder else "position_ids"
	if (
	attention_mask is not None
	and kwargs.get(position_ids_key) is None
	and position_ids_key in set(inspect.signature(self.forward).parameters.keys())
	):
	position_ids = attention_mask.long().cumsum(-1) - 1
	position_ids.masked_fill_(attention_mask == 0, 1)
	kwargs[position_ids_key] = position_ids # placed in kwargs for further processing (see below)

	# 5. Slice model inputs if it's an input that should have the same length as `input_ids`
	for model_input_name in ["position_ids", "token_type_ids", "decoder_position_ids"]:
	model_input = kwargs.get(model_input_name)
	if model_input is not None:
	if past_key_values is not None:
	current_input_length = (
	model_inputs["inputs_embeds"].shape[1]
	if model_inputs.get("inputs_embeds") is not None
	else model_inputs[input_ids_key].shape[1]
	)
	model_input = model_input[:, -current_input_length:]
	model_input = model_input.clone(memory_format=torch.contiguous_format)
	model_inputs[model_input_name] = model_input

	# 6. Create 4D attention mask is we are using a compilable cache (important for performant compiled forward
	# pass)
	if (
	isinstance(past_key_values, Cache)
	and past_key_values.is_compileable
	and attention_mask is not None
	and attention_mask.ndim == 2
	):
	if not self.config.is_encoder_decoder and model_inputs["inputs_embeds"] is not None:
	batch_size, sequence_length, _ = model_inputs["inputs_embeds"].shape
	else:
	batch_size, sequence_length = model_inputs[input_ids_key].shape[:2]

	# Create the causal mask with fixed shape in advance, to reduce recompilations. If the function to create
	# the 4D causal mask exists, it should be present in the base model (XXXModel class) or in its decoder.
	base_model = getattr(self, self.base_model_prefix, self)
	decoder = base_model.get_decoder() if hasattr(base_model, "get_decoder") else None
	causal_mask_creation_function = getattr(
	base_model, "_prepare_4d_causal_attention_mask_with_cache_position", None
	)
	if causal_mask_creation_function is None and decoder is not None: # it may be in the decoder
	causal_mask_creation_function = getattr(
	decoder, "_prepare_4d_causal_attention_mask_with_cache_position", None
	)

	# If it's not defined, it means the model uses the new general mask API
	if causal_mask_creation_function is None: # can't be found
	token_type_ids = model_inputs.get("token_type_ids")
	position_ids = model_inputs.get(position_ids_key)
	# Some models may overwrite the general one
	causal_mask_creation_function = getattr(self, "create_masks_for_generate", create_masks_for_generate)
	attention_mask = causal_mask_creation_function(
	config=self.config,
	# we only need batch size, seq_length and dtype here - we don't care about the values of the embeddings
	input_embeds=torch.empty((batch_size, sequence_length), dtype=self.dtype),
	attention_mask=attention_mask,
	cache_position=cache_position,
	past_key_values=past_key_values,
	position_ids=position_ids,
	token_type_ids=token_type_ids,
	)
	else:
	attention_mask = causal_mask_creation_function(
	attention_mask,
	sequence_length=sequence_length,
	target_length=past_key_values.get_max_cache_shape(),
	dtype=self.dtype,
	cache_position=cache_position,
	batch_size=batch_size,
	config=self.config,
	past_key_values=past_key_values,
	)
	if attention_mask is not None:
	model_inputs[attention_mask_key] = attention_mask

	if encoder_attention_mask is not None:
	model_inputs["attention_mask"] = encoder_attention_mask

	# 7. Forward ALL kwargs that are uninitialized (e.g. `use_cache`).
	for key, value in kwargs.items():
	if key not in model_inputs:
	model_inputs[key] = value

	# 8. Remove unexpected `generate` inputs (TODO @joao: fix trainer and examples)
	model_inputs.pop("labels", None)
	return model_inputs

	def _prepare_model_inputs(
	self,
	inputs: Optional[torch.Tensor] = None,
	bos_token_id: Optional[torch.Tensor] = None,
	model_kwargs: Optional[dict[str, torch.Tensor]] = None,
	) -> tuple[torch.Tensor, Optional[str], dict[str, torch.Tensor]]:
	"""
	This function extracts the model-specific `inputs` for generation.
	"""
	# 1. retrieve all kwargs that are non-None or non-model input related.
	# some encoder-decoder models have different names for model and encoder
	if (
	self.config.is_encoder_decoder
	and hasattr(self, "encoder")
	and self.encoder.main_input_name != self.main_input_name
	):
	input_name = self.encoder.main_input_name
	else:
	input_name = self.main_input_name

	model_kwargs = {k: v for k, v in model_kwargs.items() if v is not None or k != input_name}

	# 2. check whether model_input_name is passed as kwarg
	# if yes and `inputs` is None use kwarg inputs
	inputs_kwarg = model_kwargs.pop(input_name, None)
	if inputs_kwarg is not None and inputs is not None:
	raise ValueError(
	f"`inputs`: {inputs}` were passed alongside {input_name} which is not allowed. "
	f"Make sure to either pass {inputs} or {input_name}=..."
	)
	elif inputs_kwarg is not None:
	inputs = inputs_kwarg

	# 3. In the presence of `inputs_embeds` for text models:
	# - decoder-only models should complain if the user attempts to pass `inputs_embeds`, but the model
	# doesn't have its forwarding implemented. `inputs_embeds` is kept in `model_kwargs` and can coexist with
	# input_ids (`inputs_embeds` will be used in the 1st generation step, as opposed to `input_ids`)
	# - encoder-decoder models should complain if the user attempts to pass `inputs_embeds` and `input_ids`, and
	# pull the former to inputs. It will be used in place of `input_ids` to get the encoder hidden states.
	if input_name == "input_ids" and "inputs_embeds" in model_kwargs:
	if model_kwargs["inputs_embeds"] is None:
	model_kwargs.pop("inputs_embeds")
	elif not self.config.is_encoder_decoder:
	has_inputs_embeds_forwarding = "inputs_embeds" in set(
	inspect.signature(self.prepare_inputs_for_generation).parameters.keys()
	)
	if not has_inputs_embeds_forwarding:
	raise ValueError(
	f"You passed `inputs_embeds` to `.generate()`, but the model class {self.__class__.__name__} "
	"doesn't have its forwarding implemented. See the GPT2 implementation for an example "
	"(https://github.com/huggingface/transformers/pull/21405), and feel free to open a PR with it!"
	)
	# In this case, `input_ids` is moved to the `model_kwargs`, so a few automations (like the creation of
	# the attention mask) can rely on the actual model input.
	model_kwargs["input_ids"] = self._maybe_initialize_input_ids_for_generation(
	inputs, bos_token_id, model_kwargs=model_kwargs
	)
	inputs, input_name = model_kwargs["inputs_embeds"], "inputs_embeds"
	else:
	if inputs is not None:
	raise ValueError("You passed `inputs_embeds` and `input_ids` to `.generate()`. Please pick one.")
	inputs, input_name = model_kwargs["inputs_embeds"], "inputs_embeds"

	# 4. if `inputs` is still None, try to create `input_ids` from BOS token
	inputs = self._maybe_initialize_input_ids_for_generation(inputs, bos_token_id, model_kwargs)
	return inputs, input_name, model_kwargs

	def _maybe_initialize_input_ids_for_generation(
	self,
	inputs: Optional[torch.Tensor] = None,
	bos_token_id: Optional[torch.Tensor] = None,
	model_kwargs: Optional[dict[str, torch.Tensor]] = None,
	) -> torch.LongTensor:
	"""Initializes input ids for generation, if necessary."""
	if inputs is not None:
	return inputs

	encoder_outputs = model_kwargs.get("encoder_outputs")
	if self.config.is_encoder_decoder and encoder_outputs is not None:
	# make dummy input_ids with value -100, as a sanity check ensuring that they won't be used for encoding
	shape = encoder_outputs.last_hidden_state.size()[:-1]
	return torch.ones(shape, dtype=torch.long, device=self.device) * -100

	# If there is some tensor in `model_kwargs`, we can infer the batch size from it. This is helpful with
	# soft-prompting or in multimodal implementations built on top of decoder-only language models.
	batch_size = 1
	for value in model_kwargs.values():
	if isinstance(value, torch.Tensor):
	batch_size = value.shape[0]
	break

	if "inputs_embeds" in model_kwargs:
	return torch.ones((batch_size, 0), dtype=torch.long, device=self.device)

	if bos_token_id is None:
	raise ValueError("`bos_token_id` has to be defined when no `input_ids` are provided.")

	return torch.ones((batch_size, 1), dtype=torch.long, device=self.device) * bos_token_id

	def _prepare_attention_mask_for_generation(
	self,
	inputs_tensor: torch.Tensor,
	generation_config: GenerationConfig,
	model_kwargs: dict[str, Any],
	) -> torch.LongTensor:
	pad_token_id = generation_config._pad_token_tensor
	eos_token_id = generation_config._eos_token_tensor

	# `input_ids` may be present in the model kwargs, instead of being the main input (e.g. multimodal model)
	if "input_ids" in model_kwargs and model_kwargs["input_ids"].shape[1] > 0:
	inputs_tensor = model_kwargs["input_ids"]

	# No information for attention mask inference -> return default attention mask
	default_attention_mask = torch.ones(inputs_tensor.shape[:2], dtype=torch.long, device=inputs_tensor.device)
	if pad_token_id is None:
	return default_attention_mask

	is_input_ids = len(inputs_tensor.shape) == 2 and inputs_tensor.dtype in [torch.int, torch.long]
	if not is_input_ids:
	return default_attention_mask

	is_pad_token_in_inputs = (pad_token_id is not None) and (
	isin_mps_friendly(elements=inputs_tensor, test_elements=pad_token_id).any()
	)
	is_pad_token_not_equal_to_eos_token_id = (eos_token_id is None) or ~(
	isin_mps_friendly(elements=eos_token_id, test_elements=pad_token_id).any()
	)
	can_infer_attention_mask = is_pad_token_in_inputs * is_pad_token_not_equal_to_eos_token_id
	attention_mask_from_padding = inputs_tensor.ne(pad_token_id).long()

	attention_mask = (
	attention_mask_from_padding * can_infer_attention_mask + default_attention_mask * ~can_infer_attention_mask
	)
	return attention_mask

	def _prepare_encoder_decoder_kwargs_for_generation(
	self,
	inputs_tensor: torch.Tensor,
	model_kwargs,
	model_input_name: Optional[str],
	generation_config: GenerationConfig,
	) -> dict[str, Any]:
	# 1. get encoder
	encoder = self.get_encoder()
	# Compatibility with Accelerate big model inference: we need the encoder to outputs stuff on the same device
	# as the inputs.
	if hasattr(self, "hf_device_map"):
	if hasattr(encoder, "_hf_hook"):
	encoder._hf_hook.io_same_device = True
	else:
	add_hook_to_module(encoder, AlignDevicesHook(io_same_device=True))

	# 2. Prepare encoder args and encoder kwargs from model kwargs and generation config.
	irrelevant_prefix = ["decoder_", "cross_attn", "use_cache"]
	encoder_kwargs = {
	argument: value
	for argument, value in model_kwargs.items()
	if not any(argument.startswith(p) for p in irrelevant_prefix)
	}
	encoder_signature = set(inspect.signature(encoder.forward).parameters)
	encoder_accepts_wildcard = "kwargs" in encoder_signature or "model_kwargs" in encoder_signature
	if not encoder_accepts_wildcard:
	encoder_kwargs = {
	argument: value for argument, value in encoder_kwargs.items() if argument in encoder_signature
	}
	encoder_kwargs["output_attentions"] = generation_config.output_attentions
	encoder_kwargs["output_hidden_states"] = generation_config.output_hidden_states

	# 3. make sure that encoder returns `ModelOutput`
	model_input_name = model_input_name if model_input_name is not None else self.main_input_name
	encoder_kwargs["return_dict"] = True
	encoder_kwargs[model_input_name] = inputs_tensor
	model_kwargs["encoder_outputs"]: ModelOutput = encoder(**encoder_kwargs) # type: ignore

	return model_kwargs

	def _prepare_decoder_input_ids_for_generation(
	self,
	batch_size: int,
	model_input_name: str,
	model_kwargs: dict[str, torch.Tensor],
	decoder_start_token_id: torch.Tensor,
	device: Optional[torch.device] = None,
	) -> tuple[torch.LongTensor, dict[str, torch.Tensor]]:
	"""Prepares `decoder_input_ids` for generation with encoder-decoder models"""
	# 1. Check whether the user has defined `decoder_input_ids` manually. To facilitate in terms of input naming,
	# we also allow the user to pass it under `input_ids`, if the encoder does not use it as the main input.
	if model_kwargs is not None and "decoder_input_ids" in model_kwargs:
	decoder_input_ids = model_kwargs.pop("decoder_input_ids")
	elif "input_ids" in model_kwargs and model_input_name != "input_ids":
	decoder_input_ids = model_kwargs.pop("input_ids")
	else:
	decoder_input_ids = None

	# 2. `decoder_start_token_id` must have shape (batch_size, 1)
	if device is None:
	device = self.device
	if decoder_start_token_id.ndim == 1:
	if decoder_start_token_id.shape[0] != batch_size:
	raise ValueError(
	f"`decoder_start_token_id` expected to have length {batch_size} but got {decoder_start_token_id.shape[0]}"
	)
	decoder_start_token_id = decoder_start_token_id.view(-1, 1)
	else:
	decoder_start_token_id = (
	torch.ones((batch_size, 1), dtype=torch.long, device=device) * decoder_start_token_id
	)

	# 3. Encoder-decoder models expect the `decoder_input_ids` to start with a special token. Let's ensure that.
	# no user input -> use decoder_start_token_id as decoder_input_ids
	if decoder_input_ids is None:
	decoder_input_ids = decoder_start_token_id
	# exception: Donut checkpoints have task-specific decoder starts and don't expect a BOS token. Note that the
	# original checkpoints can't be detected through `self.__class__.__name__.lower()`, needing custom logic.
	# See: https://github.com/huggingface/transformers/pull/31470
	elif "donut" in self.__class__.__name__.lower() or (
	self.config.model_type == "vision-encoder-decoder" and "donut" in self.config.encoder.model_type.lower()
	):
	pass
	elif self.config.model_type == "whisper":
	pass
	# user input but doesn't start with decoder_start_token_id -> prepend decoder_start_token_id (and adjust
	# decoder_attention_mask if provided)
	elif (decoder_input_ids[:, 0] != decoder_start_token_id[:, 0]).all().item():
	decoder_input_ids = torch.cat([decoder_start_token_id, decoder_input_ids], dim=-1)
	if "decoder_attention_mask" in model_kwargs:
	decoder_attention_mask = model_kwargs["decoder_attention_mask"]
	decoder_attention_mask = torch.cat(
	(torch.ones_like(decoder_attention_mask)[:, :1], decoder_attention_mask),
	dim=-1,
	)
	model_kwargs["decoder_attention_mask"] = decoder_attention_mask

	return decoder_input_ids, model_kwargs

	@staticmethod
	def _expand_inputs_for_generation(
	expand_size: int = 1,
	is_encoder_decoder: bool = False,
	input_ids: Optional[torch.LongTensor] = None,
	**model_kwargs,
	) -> tuple[torch.LongTensor, dict[str, Any]]:
	"""Expands tensors from [batch_size, ...] to [batch_size * expand_size, ...]"""
	# Do not call torch.repeat_interleave if expand_size is 1 because it clones
	# the input tensor and thus requires more memory although no change is applied
	if expand_size == 1:
	return input_ids, model_kwargs

	def _expand_dict_for_generation(dict_to_expand):
	for key in dict_to_expand:
	if (
	key != "cache_position"
	and dict_to_expand[key] is not None
	and isinstance(dict_to_expand[key], torch.Tensor)
	):
	dict_to_expand[key] = dict_to_expand[key].repeat_interleave(expand_size, dim=0)
	return dict_to_expand

	if input_ids is not None:
	input_ids = input_ids.repeat_interleave(expand_size, dim=0)

	model_kwargs = _expand_dict_for_generation(model_kwargs)

	if is_encoder_decoder:
	if model_kwargs.get("encoder_outputs") is None:
	raise ValueError("If `is_encoder_decoder` is True, make sure that `encoder_outputs` is defined.")
	model_kwargs["encoder_outputs"] = _expand_dict_for_generation(model_kwargs["encoder_outputs"])

	return input_ids, model_kwargs

	def _update_model_kwargs_for_generation(
	self,
	outputs: ModelOutput,
	model_kwargs: dict[str, Any],
	is_encoder_decoder: bool = False,
	num_new_tokens: int = 1,
	) -> dict[str, Any]:
	# update past_key_values keeping its naming used in model code
	for possible_cache_name in ALL_CACHE_NAMES:
	if possible_cache_name in outputs:
	# TODO (joao): remove output/input mismatch when these old models (xlnet, reformer) are deprecated
	if possible_cache_name in ("past_buckets_states", "mems"):
	cache_name = "past_key_values"
	else:
	cache_name = possible_cache_name
	model_kwargs[cache_name] = getattr(outputs, possible_cache_name)
	break

	# update token_type_ids with last value
	if "token_type_ids" in model_kwargs:
	token_type_ids = model_kwargs["token_type_ids"]
	model_kwargs["token_type_ids"] = torch.cat([token_type_ids, token_type_ids[:, -1].unsqueeze(-1)], dim=-1)

	if not is_encoder_decoder:
	# update attention mask
	if "attention_mask" in model_kwargs:
	attention_mask = model_kwargs["attention_mask"]
	model_kwargs["attention_mask"] = torch.cat(
	[attention_mask, attention_mask.new_ones((attention_mask.shape[0], 1))], dim=-1
	)
	else:
	# update decoder attention mask
	if "decoder_attention_mask" in model_kwargs:
	decoder_attention_mask = model_kwargs["decoder_attention_mask"]
	model_kwargs["decoder_attention_mask"] = torch.cat(
	[decoder_attention_mask, decoder_attention_mask.new_ones((decoder_attention_mask.shape[0], 1))],
	dim=-1,
	)

	if model_kwargs.get("use_cache", True):
	model_kwargs["cache_position"] = model_kwargs["cache_position"][-1:] + num_new_tokens
	else:
	past_positions = model_kwargs.pop("cache_position")
	new_positions = torch.arange(
	past_positions[-1] + 1, past_positions[-1] + num_new_tokens + 1, dtype=past_positions.dtype
	).to(past_positions.device)
	model_kwargs["cache_position"] = torch.cat((past_positions, new_positions))
	return model_kwargs

	def _get_candidate_generator(
	self,
	generation_config: GenerationConfig,
	input_ids: torch.LongTensor,
	inputs_tensor: torch.Tensor,
	logits_processor: LogitsProcessorList,
	model_kwargs: dict[str, Any],
	assistant_model: Optional["PreTrainedModel"] = None,
	target_tokenizer: Optional["PreTrainedTokenizerBase"] = None,
	assistant_tokenizer: Optional["PreTrainedTokenizerBase"] = None,
	) -> CandidateGenerator:
	"""
	Returns the candidate generator to be used in `assisted_generation`
	"""
	different_tokenizers = all(v is not None for v in (assistant_model, target_tokenizer, assistant_tokenizer))

	if generation_config.assistant_early_exit is not None:
	candidate_generator = EarlyExitCandidateGenerator(
	input_ids=input_ids,
	assistant_model=self,
	generation_config=generation_config,
	model_kwargs=model_kwargs,
	inputs_tensor=inputs_tensor,
	logits_processor=logits_processor,
	)
	elif generation_config.prompt_lookup_num_tokens is not None:
	candidate_generator = PromptLookupCandidateGenerator(
	eos_token_id=generation_config._eos_token_tensor,
	num_output_tokens=generation_config.prompt_lookup_num_tokens,
	max_matching_ngram_size=generation_config.max_matching_ngram_size or 2,
	max_length=generation_config.max_length,
	logits_processor=logits_processor,
	vocab_size=self.config.get_text_config().vocab_size,
	)
	elif different_tokenizers:
	if generation_config.do_sample is True:
	atm_translator = AssistantVocabTranslatorCache.get_translator(
	target_tokenizer,
	assistant_tokenizer,
	self.config.get_text_config().vocab_size,
	assistant_model=assistant_model,
	assistant_prune_lm_head=True, # prune LM head of assistant model
	)
	# Since we prune the LM head, we cannot use the repetition penalty on the assistant model due to mismatches between token ids and logits index
	assistant_model.generation_config.repetition_penalty = None
	candidate_generator = UniversalSpeculativeDecodingGenerator(
	input_ids=input_ids,
	assistant_model=assistant_model,
	generation_config=generation_config,
	model_kwargs=model_kwargs,
	inputs_tensor=inputs_tensor,
	logits_processor=logits_processor,
	target_tokenizer=target_tokenizer,
	assistant_tokenizer=assistant_tokenizer,
	atm_translator=atm_translator,
	)
	elif generation_config.do_sample is False:
	candidate_generator = AssistedCandidateGeneratorDifferentTokenizers(
	input_ids=input_ids,
	assistant_model=assistant_model,
	generation_config=generation_config,
	model_kwargs=model_kwargs,
	inputs_tensor=inputs_tensor,
	logits_processor=logits_processor,
	target_tokenizer=target_tokenizer,
	assistant_tokenizer=assistant_tokenizer,
	)
	else:
	raise ValueError(
	f"Invalid value for `do_sample`: expected a boolean, got {type(generation_config.do_sample).__name__}"
	)
	else:
	candidate_generator = AssistedCandidateGenerator(
	input_ids=input_ids,
	assistant_model=assistant_model,
	generation_config=generation_config,
	model_kwargs=model_kwargs,
	inputs_tensor=inputs_tensor,
	logits_processor=logits_processor,
	)
	return candidate_generator

	def _get_logits_processor(
	self,
	generation_config: GenerationConfig,
	input_ids_seq_length: Optional[int] = None,
	encoder_input_ids: Optional[torch.LongTensor] = None,
	prefix_allowed_tokens_fn: Optional[Callable[[int, torch.Tensor], list[int]]] = None,
	logits_processor: Optional[LogitsProcessorList] = None,
	device: Optional[str] = None,
	model_kwargs: Optional[dict[str, Any]] = None,
	negative_prompt_ids: Optional[torch.Tensor] = None,
	negative_prompt_attention_mask: Optional[torch.Tensor] = None,
	) -> LogitsProcessorList:
	"""
	This class returns a [`LogitsProcessorList`] list object that contains all relevant [`LogitsProcessor`]
	instances used to modify the scores of the language model head.
	"""
	# instantiate processors list
	processors = LogitsProcessorList()
	if logits_processor is None:
	logits_processor = []

	if generation_config.guidance_scale is not None and generation_config.guidance_scale != 1:
	processors.append(
	UnbatchedClassifierFreeGuidanceLogitsProcessor(
	generation_config.guidance_scale,
	self,
	unconditional_ids=negative_prompt_ids,
	unconditional_attention_mask=negative_prompt_attention_mask,
	use_cache=generation_config.use_cache,
	)
	)
	if generation_config.sequence_bias is not None:
	processors.append(SequenceBiasLogitsProcessor(sequence_bias=generation_config.sequence_bias))

	if (
	generation_config.encoder_repetition_penalty is not None
	and generation_config.encoder_repetition_penalty != 1.0
	):
	if len(encoder_input_ids.shape) == 2:
	processors.append(
	EncoderRepetitionPenaltyLogitsProcessor(
	penalty=generation_config.encoder_repetition_penalty,
	encoder_input_ids=encoder_input_ids,
	)
	)
	else:
	warnings.warn(
	"Passing `encoder_repetition_penalty` requires some form of `input_ids` to be passed to "
	"`generate`, ignoring the argument.",
	UserWarning,
	)
	if generation_config.repetition_penalty is not None and generation_config.repetition_penalty != 1.0:
	processors.append(RepetitionPenaltyLogitsProcessor(penalty=generation_config.repetition_penalty))
	if generation_config.no_repeat_ngram_size is not None and generation_config.no_repeat_ngram_size > 0:
	processors.append(NoRepeatNGramLogitsProcessor(generation_config.no_repeat_ngram_size))
	if (
	generation_config.encoder_no_repeat_ngram_size is not None
	and generation_config.encoder_no_repeat_ngram_size > 0
	):
	if len(encoder_input_ids.shape) == 2:
	processors.append(
	EncoderNoRepeatNGramLogitsProcessor(
	generation_config.encoder_no_repeat_ngram_size,
	encoder_input_ids,
	)
	)
	else:
	warnings.warn(
	"Passing `encoder_no_repeat_ngram_size` requires some form of `input_ids` to be passed to "
	"`generate`, ignoring the argument.",
	UserWarning,
	)
	if generation_config.bad_words_ids is not None:
	processors.append(
	NoBadWordsLogitsProcessor(
	generation_config.bad_words_ids,
	generation_config._eos_token_tensor,
	)
	)
	if (
	generation_config.min_length is not None
	and getattr(generation_config, "_eos_token_tensor", None) is not None
	and generation_config.min_length > 0
	):
	processors.append(
	MinLengthLogitsProcessor(
	generation_config.min_length,
	generation_config._eos_token_tensor,
	device=device,
	)
	)
	if (
	generation_config.min_new_tokens is not None
	and getattr(generation_config, "_eos_token_tensor", None) is not None
	and generation_config.min_new_tokens > 0
	):
	processors.append(
	MinNewTokensLengthLogitsProcessor(
	input_ids_seq_length,
	generation_config.min_new_tokens,
	generation_config._eos_token_tensor,
	device=device,
	)
	)
	if prefix_allowed_tokens_fn is not None:
	processors.append(
	PrefixConstrainedLogitsProcessor(
	prefix_allowed_tokens_fn,
	generation_config.num_beams,
	)
	)
	if generation_config.forced_bos_token_id is not None:
	processors.append(
	ForcedBOSTokenLogitsProcessor(
	generation_config.forced_bos_token_id,
	)
	)
	if generation_config.forced_eos_token_id is not None:
	processors.append(
	ForcedEOSTokenLogitsProcessor(
	generation_config.max_length,
	generation_config.forced_eos_token_id,
	device=device,
	)
	)
	if generation_config.remove_invalid_values is True:
	processors.append(InfNanRemoveLogitsProcessor())
	if generation_config.exponential_decay_length_penalty is not None:
	processors.append(
	ExponentialDecayLengthPenalty(
	generation_config.exponential_decay_length_penalty,
	generation_config._eos_token_tensor,
	input_ids_seq_length,
	)
	)
	if generation_config.suppress_tokens is not None:
	processors.append(
	SuppressTokensLogitsProcessor(
	generation_config.suppress_tokens,
	device=device,
	)
	)
	if generation_config.begin_suppress_tokens is not None:
	begin_index = input_ids_seq_length
	begin_index = (
	begin_index
	if (input_ids_seq_length > 1 or generation_config.forced_bos_token_id is None)
	else begin_index + 1
	)
	processors.append(
	SuppressTokensAtBeginLogitsProcessor(
	generation_config.begin_suppress_tokens,
	begin_index,
	device=device,
	)
	)

	# TODO (joao): find a strategy to specify the order of the processors
	processors = self._merge_criteria_processor_list(processors, logits_processor)

	# Processors previously known as `LogitsWarpers`, only applied with sampling strategies
	if generation_config.do_sample:
	# In beam methods, we need to keep at least one non-eos token to explore continuations that might have a
	# better score (i.e. keep len(list(generation_config._eos_token_tensor)) + 1)
	if generation_config.num_beams > 1:
	if isinstance(generation_config._eos_token_tensor, list):
	min_tokens_to_keep = len(generation_config._eos_token_tensor) + 1
	elif isinstance(generation_config._eos_token_tensor, torch.Tensor):
	min_tokens_to_keep = generation_config._eos_token_tensor.shape[0] + 1
	else:
	min_tokens_to_keep = 2
	else:
	min_tokens_to_keep = 1

	# the following idea is largely copied from this PR: https://github.com/huggingface/transformers/pull/5420/files
	# all samplers can be found in `generation_utils_samplers.py`
	if generation_config.temperature is not None and generation_config.temperature != 1.0:
	processors.append(TemperatureLogitsWarper(generation_config.temperature))
	if generation_config.top_k is not None and generation_config.top_k != 0:
	processors.append(
	TopKLogitsWarper(top_k=generation_config.top_k, min_tokens_to_keep=min_tokens_to_keep)
	)
	if generation_config.top_p is not None and generation_config.top_p < 1.0:
	processors.append(
	TopPLogitsWarper(top_p=generation_config.top_p, min_tokens_to_keep=min_tokens_to_keep)
	)
	if generation_config.min_p is not None:
	# Applied after temperature scaling (see https://github.com/ggerganov/llama.cpp/pull/3841#issuecomment-2073826084)
	processors.append(
	MinPLogitsWarper(min_p=generation_config.min_p, min_tokens_to_keep=min_tokens_to_keep)
	)
	if generation_config.typical_p is not None and generation_config.typical_p < 1.0:
	processors.append(
	TypicalLogitsWarper(mass=generation_config.typical_p, min_tokens_to_keep=min_tokens_to_keep)
	)
	if generation_config.epsilon_cutoff is not None and 0.0 < generation_config.epsilon_cutoff < 1.0:
	processors.append(
	EpsilonLogitsWarper(
	epsilon=generation_config.epsilon_cutoff, min_tokens_to_keep=min_tokens_to_keep
	)
	)
	if generation_config.eta_cutoff is not None and 0.0 < generation_config.eta_cutoff < 1.0:
	processors.append(
	EtaLogitsWarper(
	epsilon=generation_config.eta_cutoff, min_tokens_to_keep=min_tokens_to_keep, device=device
	)
	)

	# Watermarking should be after all logits processing is finished (see #34630)
	if generation_config.watermarking_config is not None:
	processors.append(
	generation_config.watermarking_config.construct_processor(
	self.config.get_text_config().vocab_size, device
	)
	)

	# `LogitNormalization` should always be the last logit processor, when present
	if generation_config.renormalize_logits is True:
	processors.append(LogitNormalization())
	return processors

	def _get_stopping_criteria(
	self,
	generation_config: GenerationConfig,
	stopping_criteria: Optional[StoppingCriteriaList],
	tokenizer: Optional["PreTrainedTokenizerBase"] = None,
	) -> StoppingCriteriaList:
	criteria = StoppingCriteriaList()
	if generation_config.max_length is not None:
	max_position_embeddings = getattr(self.config, "max_position_embeddings", None)
	criteria.append(
	MaxLengthCriteria(
	max_length=generation_config.max_length,
	max_position_embeddings=max_position_embeddings,
	)
	)
	if generation_config.max_time is not None:
	criteria.append(MaxTimeCriteria(max_time=generation_config.max_time))
	if generation_config.stop_strings is not None:
	if tokenizer is None:
	raise ValueError(
	"There are one or more stop strings, either in the arguments to `generate` or in the "
	"model's generation config, but we could not locate a tokenizer. When generating with "
	"stop strings, you must pass the model's tokenizer to the `tokenizer` argument of `generate`."
	)
	criteria.append(StopStringCriteria(stop_strings=generation_config.stop_strings, tokenizer=tokenizer))
	if generation_config._eos_token_tensor is not None:
	criteria.append(EosTokenCriteria(eos_token_id=generation_config._eos_token_tensor))
	if (
	generation_config.is_assistant
	and generation_config.assistant_confidence_threshold is not None
	and generation_config.assistant_confidence_threshold > 0
	):
	criteria.append(
	ConfidenceCriteria(assistant_confidence_threshold=generation_config.assistant_confidence_threshold)
	)
	criteria = self._merge_criteria_processor_list(criteria, stopping_criteria)
	return criteria

	def _merge_criteria_processor_list(
	self,
	default_list: Union[LogitsProcessorList, StoppingCriteriaList],
	custom_list: Union[LogitsProcessorList, StoppingCriteriaList],
	) -> Union[LogitsProcessorList, StoppingCriteriaList]:
	"""
	Merge user-defined processors/criteria with the ones instantiated inside `generate`. In case the same
	processor/criteria is present on both lists, use the user-defined one.

	(Note: up to v4.49.0, this function threw an exception is the same logit processor was found twice.)
	"""
	if len(custom_list) == 0:
	return default_list

	final_list = type(default_list)()
	for default in default_list:
	using_custom = False
	for custom in custom_list:
	if type(custom) is type(default):
	object_type = "stopping criteria" if isinstance(custom, StoppingCriteria) else "logits processor"
	logger.warning_once(
	f"A custom {object_type} of type {type(custom)} has been passed to `.generate()`, but it "
	f"was also created in `.generate()`, given its parameterization. The custom {type(custom)} "
	f"will take precedence. Please check the docstring of {type(custom)} to see related "
	"`.generate()` flags."
	)
	final_list.append(custom)
	using_custom = True
	break
	if not using_custom:
	final_list.append(default)

	for custom in custom_list:
	if custom not in final_list:
	final_list.append(custom)
	return final_list

	def compute_transition_scores(
	self,
	sequences: torch.Tensor,
	scores: tuple[torch.Tensor],
	beam_indices: Optional[torch.Tensor] = None,
	normalize_logits: bool = False,
	) -> torch.Tensor:
	"""
	Computes the transition scores of sequences given the generation scores (and beam indices, if beam search was
	used). This is a convenient method to quickly obtain the scores of the selected tokens at generation time.

	Parameters:
	sequences (`torch.LongTensor`):
	The generated sequences. The second dimension (sequence_length) is either equal to `max_length` or
	shorter if all batches finished early due to the `eos_token_id`.
	scores (`tuple(torch.FloatTensor)`):
	Transition scores for each vocabulary token at each generation step. Beam transition scores consisting
	of log probabilities of tokens conditioned on log softmax of previously generated tokens in this beam.
	Tuple of `torch.FloatTensor` with up to `max_new_tokens` elements (one element for each generated token),
	with each tensor of shape `(batch_size*num_beams, config.vocab_size)`.
	beam_indices (`torch.LongTensor`, optional):
	Beam indices of generated token id at each generation step. `torch.LongTensor` of shape
	`(batch_size*num_return_sequences, sequence_length)`. Only required if a `num_beams>1` at
	generate-time.
	normalize_logits (`bool`, optional, defaults to `False`):
	Whether to normalize the logits (which, for legacy reasons, may be unnormalized).

	Return:
	`torch.Tensor`: A `torch.Tensor` of shape `(batch_size*num_return_sequences, sequence_length)` containing
	the transition scores (logits)

	Examples:

	```python
	>>> from transformers import GPT2Tokenizer, AutoModelForCausalLM
	>>> import numpy as np

	>>> tokenizer = GPT2Tokenizer.from_pretrained("gpt2")
	>>> model = AutoModelForCausalLM.from_pretrained("openai-community/gpt2")
	>>> tokenizer.pad_token_id = tokenizer.eos_token_id
	>>> inputs = tokenizer(["Today is"], return_tensors="pt")

	>>> # Example 1: Print the scores for each token generated with Greedy Search
	>>> outputs = model.generate(**inputs, max_new_tokens=5, return_dict_in_generate=True, output_scores=True)
	>>> transition_scores = model.compute_transition_scores(
	... outputs.sequences, outputs.scores, normalize_logits=True
	... )
	>>> # input_length is the length of the input prompt for decoder-only models, like the GPT family, and 1 for
	>>> # encoder-decoder models, like BART or T5.
	>>> input_length = 1 if model.config.is_encoder_decoder else inputs.input_ids.shape[1]
	>>> generated_tokens = outputs.sequences[:, input_length:]
	>>> for tok, score in zip(generated_tokens[0], transition_scores[0]):
	... # \| token \| token string \| log probability \| probability
	... print(f"\| {tok:5d} \| {tokenizer.decode(tok):8s} \| {score.numpy():.3f} \| {np.exp(score.numpy()):.2%}")
	\| 262 \| the \| -1.414 \| 24.33%
	\| 1110 \| day \| -2.609 \| 7.36%
	\| 618 \| when \| -2.010 \| 13.40%
	\| 356 \| we \| -1.859 \| 15.58%
	\| 460 \| can \| -2.508 \| 8.14%

	>>> # Example 2: Reconstruct the sequence scores from Beam Search
	>>> outputs = model.generate(
	... **inputs,
	... max_new_tokens=5,
	... num_beams=4,
	... num_return_sequences=4,
	... return_dict_in_generate=True,
	... output_scores=True,
	... )
	>>> transition_scores = model.compute_transition_scores(
	... outputs.sequences, outputs.scores, outputs.beam_indices, normalize_logits=False
	... )
	>>> # If you sum the generated tokens' scores and apply the length penalty, you'll get the sequence scores.
	>>> # Tip 1: recomputing the scores is only guaranteed to match with `normalize_logits=False`. Depending on the
	>>> # use case, you might want to recompute it with `normalize_logits=True`.
	>>> # Tip 2: the output length does NOT include the input length
	>>> output_length = np.sum(transition_scores.numpy() < 0, axis=1)
	>>> length_penalty = model.generation_config.length_penalty
	>>> reconstructed_scores = transition_scores.sum(axis=1) / (output_length**length_penalty)
	>>> print(np.allclose(outputs.sequences_scores, reconstructed_scores))
	True
	```"""
	# 1. In absence of `beam_indices`, we can assume that we come from e.g. greedy search, which is equivalent
	# to a beam search approach were the first (and only) beam is always selected
	if beam_indices is None:
	beam_indices = torch.arange(scores[0].shape[0]).view(-1, 1).to(sequences.device)
	beam_indices = beam_indices.expand(-1, len(scores))

	# 2. reshape scores as [batch_size*vocab_size, # generation steps] with # generation steps being
	# seq_len - input_length
	scores = torch.stack(scores).reshape(len(scores), -1).transpose(0, 1)

	# 3. Optionally normalize the logits (across the vocab dimension)
	if normalize_logits:
	scores = scores.reshape(-1, self.config.get_text_config().vocab_size, scores.shape[-1])
	scores = torch.nn.functional.log_softmax(scores, dim=1)
	scores = scores.reshape(-1, scores.shape[-1])

	# 4. cut beam_indices to longest beam length
	beam_indices_mask = beam_indices < 0
	max_beam_length = (1 - beam_indices_mask.long()).sum(-1).max()
	beam_indices = beam_indices.clone()[:, :max_beam_length]
	beam_indices_mask = beam_indices_mask[:, :max_beam_length]

	# 5. Set indices of beams that finished early to 0; such indices will be masked correctly afterwards
	beam_indices[beam_indices_mask] = 0

	# 6. multiply beam_indices with vocab size to gather correctly from scores
	beam_sequence_indices = beam_indices * self.config.get_text_config().vocab_size

	# 7. Define which indices contributed to scores
	cut_idx = sequences.shape[-1] - max_beam_length
	indices = sequences[:, cut_idx:] + beam_sequence_indices

	# 8. Compute scores
	transition_scores = scores.gather(0, indices)

	# 9. Mask out transition_scores of beams that stopped early
	transition_scores[beam_indices_mask] = 0

	return transition_scores

	def _validate_generation_mode(self, generation_mode, generation_config, generation_mode_kwargs):
	if generation_mode == GenerationMode.BEAM_SEARCH and "streamer" in generation_mode_kwargs:
	raise ValueError(
	"`streamer` cannot be used with beam search (yet!). Make sure that `num_beams` is set to 1."
	)

	if generation_mode == GenerationMode.ASSISTED_GENERATION:
	if generation_config.num_return_sequences > 1:
	raise ValueError(
	"num_return_sequences has to be 1 when doing assisted generate, "
	f"but is {generation_config.num_return_sequences}."
	)
	if self._is_stateful:
	# In assisted generation we need the ability to confirm whether the model would pick certain tokens,
	# which is not possible with stateful models (they can't reset to a previous subset of generated text)
	raise ValueError(
	f"assisted generation is not supported with stateful models, such as {self.__class__.__name__}"
	)

	if (assistant_model := generation_mode_kwargs.get("assistant_model")) is not None:
	if self.config.is_encoder_decoder and not assistant_model.config.is_encoder_decoder:
	attributes_to_check = ["encoder_attention_heads", "encoder_ffn_dim", "encoder_layers"]
	attributes_to_check = [attr for attr in dir(assistant_model.config) if attr in attributes_to_check]
	are_equal = all(
	getattr(self.config, attr) == getattr(assistant_model.config, attr) for attr in attributes_to_check
	)
	if not are_equal:
	raise ValueError(
	"The main model and the assistant don't have compatible encoder-dependent input shapes. "
	"Ensure you load the assistant with the correct encoder-decoder class, e.g. `AutoModelForSpeechSeq2Seq` for Whisper."
	)

	doc_reference = (
	"(see https://huggingface.co/docs/transformers/en/generation_strategies#universal-assisted-decoding)"
	)
	if self.config.get_text_config().vocab_size == assistant_model.config.get_text_config().vocab_size:
	if "assistant_tokenizer" in generation_mode_kwargs:
	raise ValueError(
	f"`assistant_tokenizer` is not required when the main and assistant models use the same tokenizer. Please omit `assistant_tokenizer` from `generate()` {doc_reference}."
	)
	else:
	if "tokenizer" not in generation_mode_kwargs or "assistant_tokenizer" not in generation_mode_kwargs:
	raise ValueError(
	f"The main and assistant models have different tokenizers. Please provide `tokenizer` and `assistant_tokenizer` to `generate()` {doc_reference}."
	)

	def _validate_model_kwargs(self, model_kwargs: dict[str, Any]):
	"""Validates model kwargs for generation. Generate argument typos will also be caught here."""
	# Excludes arguments that are handled before calling any model function
	if self.config.is_encoder_decoder:
	for key in ["decoder_input_ids"]:
	model_kwargs.pop(key, None)

	unused_model_args = []
	model_args = set(inspect.signature(self.prepare_inputs_for_generation).parameters)
	# `kwargs`/`model_kwargs` is often used to handle optional forward pass inputs like `attention_mask`. If
	# `prepare_inputs_for_generation` doesn't accept them, then a stricter check can be made ;)
	if "kwargs" in model_args or "model_kwargs" in model_args:
	model_args \|= set(inspect.signature(self.forward).parameters)

	# Encoder-Decoder models may also need Encoder arguments from `model_kwargs`
	if self.config.is_encoder_decoder:
	base_model = getattr(self, self.base_model_prefix, None)

	# allow encoder kwargs
	encoder = getattr(self, "encoder", None)
	# `MusicgenForConditionalGeneration` has `text_encoder` and `audio_encoder`.
	# Also, it has `base_model_prefix = "encoder_decoder"` but there is no `self.encoder_decoder`
	# TODO: A better way to handle this.
	if encoder is None and base_model is not None:
	encoder = getattr(base_model, "encoder", None)

	if encoder is not None:
	encoder_model_args = set(inspect.signature(encoder.forward).parameters)
	model_args \|= encoder_model_args

	# allow decoder kwargs
	decoder = getattr(self, "decoder", None)
	if decoder is None and base_model is not None:
	decoder = getattr(base_model, "decoder", None)

	if decoder is not None:
	decoder_model_args = set(inspect.signature(decoder.forward).parameters)
	model_args \|= {f"decoder_{x}" for x in decoder_model_args}

	# TransformersKwargs are model-agnostic attention and generation arguments such as 'output_attentions'
	for key, value in model_kwargs.items():
	if value is not None and key not in model_args and key not in TransformersKwargs.__optional_keys__:
	unused_model_args.append(key)

	if unused_model_args:
	raise ValueError(
	f"The following `model_kwargs` are not used by the model: {unused_model_args} (note: typos in the"
	" generate arguments will also show up in this list)"
	)

	def _validate_generated_length(self, generation_config, input_ids_length, has_default_max_length):
	"""Performs validation related to the resulting generated length"""
	# 1. Max length warnings related to poor parameterization
	if has_default_max_length and generation_config.max_new_tokens is None and generation_config.max_length == 20:
	# 20 is the default max_length of the generation config
	warnings.warn(
	f"Using the model-agnostic default `max_length` (={generation_config.max_length}) to control the "
	"generation length. We recommend setting `max_new_tokens` to control the maximum length of the "
	"generation.",
	UserWarning,
	)
	if input_ids_length >= generation_config.max_length:
	input_ids_string = "decoder_input_ids" if self.config.is_encoder_decoder else "input_ids"
	raise ValueError(
	f"Input length of {input_ids_string} is {input_ids_length}, but `max_length` is set to"
	f" {generation_config.max_length}. This can lead to unexpected behavior. You should consider"
	" increasing `max_length` or, better yet, setting `max_new_tokens`."
	)

	# 2. Min length warnings due to unfeasible parameter combinations
	min_length_error_suffix = (
	" Generation will stop at the defined maximum length. You should decrease the minimum length and/or "
	"increase the maximum length."
	)
	if has_default_max_length:
	min_length_error_suffix += (
	f" Note that `max_length` is set to {generation_config.max_length}, its default value."
	)
	if generation_config.min_length is not None and generation_config.min_length > generation_config.max_length:
	warnings.warn(
	f"Unfeasible length constraints: `min_length` ({generation_config.min_length}) is larger than"
	f" the maximum possible length ({generation_config.max_length})." + min_length_error_suffix,
	UserWarning,
	)
	if generation_config.min_new_tokens is not None:
	min_length = generation_config.min_new_tokens + input_ids_length
	if min_length > generation_config.max_length:
	warnings.warn(
	f"Unfeasible length constraints: `min_new_tokens` ({generation_config.min_new_tokens}), when "
	f"added to the prompt length ({input_ids_length}), is larger than"
	f" the maximum possible length ({generation_config.max_length})." + min_length_error_suffix,
	UserWarning,
	)

	def _prepare_generated_length(
	self,
	generation_config,
	has_default_max_length,
	has_default_min_length,
	model_input_name,
	input_ids_length,
	inputs_tensor,
	):
	"""Prepared max and min length in generation configs to avoid clashes between similar attributes"""

	if generation_config.max_new_tokens is not None:
	if not has_default_max_length and generation_config.max_length is not None:
	logger.warning(
	f"Both `max_new_tokens` (={generation_config.max_new_tokens}) and `max_length`(="
	f"{generation_config.max_length}) seem to have been set. `max_new_tokens` will take precedence. "
	"Please refer to the documentation for more information. "
	"(https://huggingface.co/docs/transformers/main/en/main_classes/text_generation)"
	)
	generation_config.max_length = generation_config.max_new_tokens + input_ids_length

	# if both `inputs_embeds` and `input_ids` are passed, we do not correct the length
	# otherwise we need total length [inputs-embeds-len + new-tokens-len] to not go beyond indicated `max_length``
	elif (
	model_input_name == "inputs_embeds"
	and input_ids_length != inputs_tensor.shape[1]
	and not self.config.is_encoder_decoder
	):
	generation_config.max_length -= inputs_tensor.shape[1]
	elif has_default_max_length: # by default let's always generate 20 new tokens
	if generation_config.max_length == GenerationConfig().max_length:
	generation_config.max_length = generation_config.max_length + input_ids_length
	max_position_embeddings = getattr(self.config, "max_position_embeddings", None)
	if max_position_embeddings is not None:
	generation_config.max_length = min(generation_config.max_length, max_position_embeddings)

	# same for min length
	if generation_config.min_new_tokens is not None:
	if not has_default_min_length:
	logger.warning(
	f"Both `min_new_tokens` (={generation_config.min_new_tokens}) and `min_length`(="
	f"{generation_config.min_length}) seem to have been set. `min_new_tokens` will take precedence. "
	"Please refer to the documentation for more information. "
	"(https://huggingface.co/docs/transformers/main/en/main_classes/text_generation)"
	)
	generation_config.min_length = generation_config.min_new_tokens + input_ids_length

	elif (
	model_input_name == "inputs_embeds"
	and input_ids_length != inputs_tensor.shape[1]
	and not self.config.is_encoder_decoder
	):
	generation_config.min_length = max(generation_config.min_length - inputs_tensor.shape[1], 0)

	return generation_config

	def _prepare_generation_config(
	self,
	generation_config: Optional[GenerationConfig],
	use_model_defaults: Optional[bool] = None,
	**kwargs: Any,
	) -> tuple[GenerationConfig, dict]:
	"""
	Prepares the base generation config, then applies any generation configuration options from kwargs. This
	function handles retrocompatibility with respect to configuration files.
	"""
	# parameterization priority:
	# kwargs > non-global default values in `generation_config` > `model.generation_config` > GenerationConfig()
	# TODO (joao): per-model generation config classes.

	using_model_generation_config = False
	if generation_config is None:
	# legacy: users may modify the model configuration to control generation. To trigger this legacy behavior,
	# the following conditions must be met
	# 1) the generation config must have been created from the model config (`_from_model_config` field);
	# 2) the generation config must have seen no modification since its creation (the hash is the same);
	# 3) there are non-default generation parameters in the model config.
	# 4) the user must have set new generation parameters in the model config.
	if (
	self.generation_config._from_model_config # 1)
	and self.generation_config._original_object_hash == hash(self.generation_config) # 2)
	and len(self.config._get_non_default_generation_parameters()) > 0 # 3)
	):
	new_generation_config = GenerationConfig.from_model_config(self.config)
	if new_generation_config != self.generation_config: # 4)
	warnings.warn(
	"You have modified the pretrained model configuration to control generation. This is a"
	" deprecated strategy to control generation and will be removed in v5."
	" Please use and modify the model generation configuration (see"
	" https://huggingface.co/docs/transformers/generation_strategies#default-text-generation-configuration )",
	UserWarning,
	)
	self.generation_config = new_generation_config

	generation_config = self.generation_config
	using_model_generation_config = True

	# Related to #40039: prior to this PR, models with sliding window attention were forced to have
	# `cache_implementation="hybrid"` (the static sliding window cache). For these models, we now want to use
	# the dynamic sliding window cache by default, so we UNSET `cache_implementation` if it is a default value.
	# (if we're inside this branch, then it is because we're using default values from the Hub)
	if generation_config.cache_implementation == "hybrid":
	generation_config.cache_implementation = None

	# `torch.export.export` usually raises an exception if it is called
	# with ``strict=True``. deepcopy can only be processed if ``strict=False``.
	generation_config = copy.deepcopy(generation_config)

	if not using_model_generation_config:
	# If `generation_config` is provided:
	# - `use_model_defaults`: let's fallback ALL default values to the model's generation config
	# - otherwise: legacy behavior, let's just make sure we have the tokens defined
	model_base_version = version.parse(version.parse(self.generation_config.transformers_version).base_version)
	if use_model_defaults is True or (
	use_model_defaults is None and model_base_version >= version.parse("4.50.0")
	):
	modified_values = {}
	global_default_generation_config = GenerationConfig()
	model_generation_config = self.generation_config
	# we iterate over the model's generation config: it may hold custom keys, which we'll want to copy
	for key, model_gen_config_value in model_generation_config.__dict__.items():
	if key.startswith("_") or key == "transformers_version": # metadata
	continue
	# Don't set `cache_implementation = 'hybrid'` from the model defaults, see #40135
	if key == "cache_implementation" and model_generation_config.cache_implementation == "hybrid":
	continue
	global_default_value = getattr(global_default_generation_config, key, None)
	custom_gen_config_value = getattr(generation_config, key, None)
	if (
	custom_gen_config_value == global_default_value
	and model_gen_config_value != global_default_value
	):
	modified_values[key] = model_gen_config_value
	setattr(generation_config, key, model_gen_config_value)
	# edge case: we may set `temperature=0.0` and `do_sample=False`, but the model defaults to
	# `do_sample=True`
	if generation_config.temperature == 0.0:
	generation_config.do_sample = False
	if use_model_defaults is None and len(modified_values) > 0:
	logger.warning_once(
	f"`generation_config` default values have been modified to match model-specific defaults: "
	f"{modified_values}. If this is not desired, please set these values explicitly."
	)
	else:
	if generation_config.bos_token_id is None:
	generation_config.bos_token_id = self.generation_config.bos_token_id
	if generation_config.eos_token_id is None:
	generation_config.eos_token_id = self.generation_config.eos_token_id
	if generation_config.pad_token_id is None:
	generation_config.pad_token_id = self.generation_config.pad_token_id
	if generation_config.decoder_start_token_id is None:
	generation_config.decoder_start_token_id = self.generation_config.decoder_start_token_id

	# Finally, apply any passed kwargs
	model_kwargs = generation_config.update(**kwargs)
	# And keep in model_kwargs variable output controls
	output_attentions = generation_config.output_attentions
	output_hidden_states = generation_config.output_hidden_states
	model_kwargs.update({"output_attentions": output_attentions} if output_attentions else {})
	model_kwargs.update({"output_hidden_states": output_hidden_states} if output_hidden_states else {})

	return generation_config, model_kwargs

	def _get_initial_cache_position(self, seq_length, device, model_kwargs):
	"""Calculates `cache_position` for the pre-fill stage based on `input_ids` and optionally past length"""
	# `torch.compile`-friendly `torch.arange` from a shape -- the lines below are equivalent to `torch.arange`
	if "cache_position" in model_kwargs and model_kwargs["cache_position"] is not None:
	return model_kwargs
	if "inputs_embeds" in model_kwargs and not self.config.is_encoder_decoder:
	cache_position = torch.ones_like(model_kwargs["inputs_embeds"][0, :, 0], dtype=torch.int64).cumsum(0) - 1
	elif "decoder_inputs_embeds" in model_kwargs and self.config.is_encoder_decoder:
	cache_position = (
	torch.ones_like(model_kwargs["decoder_inputs_embeds"][0, :, 0], dtype=torch.int64).cumsum(0) - 1
	)
	else:
	cache_position = torch.ones(seq_length, dtype=torch.int64, device=device).cumsum(0) - 1

	past_length = 0
	if model_kwargs.get("past_key_values") is not None:
	cache = model_kwargs["past_key_values"]
	past_length = 0
	# Support for BC tuple cache format
	if isinstance(cache, tuple):
	past_length = cache[0][0].shape[2]
	elif hasattr(cache, "get_seq_length"):
	past_length = cache.get_seq_length()

	cache_position = cache_position[past_length:]

	model_kwargs["cache_position"] = cache_position
	return model_kwargs

	def _get_cache(self, cache_implementation: str, batch_size: int, max_cache_len: int, model_kwargs) -> Cache:
	"""
	Sets a cache for `generate`, that will persist across calls. A new cache will only be initialized a
	new `generate` call requires a larger cache or uses a different batch size.

	Returns the resulting cache object.
	"""
	requires_cross_attention_cache = (
	self.config.is_encoder_decoder or model_kwargs.get("encoder_outputs") is not None
	)
	offload_cache = "offloaded" in cache_implementation

	if hasattr(self, "_cache"):
	cache_to_check = self._cache.self_attention_cache if requires_cross_attention_cache else self._cache

	need_new_cache = (
	not hasattr(self, "_cache")
	or cache_to_check.offloading != offload_cache
	or cache_to_check.max_batch_size != batch_size
	or cache_to_check.max_cache_len < max_cache_len
	)

	if requires_cross_attention_cache and hasattr(self, "_cache"):
	need_new_cache = (
	need_new_cache
	or self._cache.cross_attention_cache.max_cache_len != model_kwargs["encoder_outputs"][0].shape[1]
	)

	if need_new_cache:
	self_attention_cache_kwargs = {
	"config": self.config.get_text_config(decoder=True),
	"max_cache_len": max_cache_len,
	"offloading": offload_cache,
	}
	self._cache = StaticCache(**self_attention_cache_kwargs)
	if requires_cross_attention_cache:
	cross_attention_cache_kwargs = {
	"config": self.config.get_text_config(decoder=True),
	"max_cache_len": model_kwargs["encoder_outputs"][0].shape[1],
	"offloading": offload_cache,
	}
	self._cache = EncoderDecoderCache(self._cache, StaticCache(**cross_attention_cache_kwargs))
	else:
	self._cache.reset()
	return self._cache

	@classmethod
	def _supports_default_dynamic_cache(cls) -> bool:
	"""
	Return `True` if current model can use a `DynamicCache` instance when initializing the `past_key_values`.
	This adds exception for some models like `Mamba` models which use their own caches
	and do not need to initialize the Cache in advance in order to save memory (because no back and forth
	`to_legacy_cache` and `from_legacy_cache` will be performed for mamba-based models).
	"""
	# NOTE: remove xlnet/reformer when the models are deprecated, non-standard model architecture/cache name
	return not cls._is_stateful and all(
	special_model_name not in cls.__name__.lower()
	for special_model_name in [
	"reformer",
	"minimax",
	"xlnet",
	"lfm2",
	"lfm2-vl",
	]
	)

	def _prepare_cache_for_generation(
	self,
	generation_config: GenerationConfig,
	model_kwargs: dict,
	generation_mode: GenerationMode,
	batch_size: int,
	max_cache_length: int,
	) -> bool:
	"""
	Prepares the cache for generation (if applicable), given `generate`'s parameterization. If a cache is
	instantiated, writes it to `model_kwargs`, under the name expected by the model.
	"""

	is_hybrid_cache = any(class_name in self.__class__.__name__.lower() for class_name in ["mamba", "falconh1"])
	cache_name = "past_key_values" if not is_hybrid_cache else "cache_params"

	requires_cross_attention_cache = (
	self.config.is_encoder_decoder or model_kwargs.get("encoder_outputs") is not None
	)

	# Quick escape route 1: if the user specifies a cache, we only need to:
	# a) check for conflicting `generate` arguments
	# b) convert to the new cache format (if the user passes a legacy cache and model supports it)
	user_defined_cache = model_kwargs.get(cache_name)
	if user_defined_cache is not None:
	if generation_config.cache_implementation is not None:
	raise ValueError(
	f"Passing both `cache_implementation` (used to initialize certain caches) and `{cache_name}` (a "
	"Cache object) is unsupported. Please use only one of the two."
	)
	if isinstance(user_defined_cache, tuple) and self._supports_default_dynamic_cache():
	logger.warning_once(
	"Passing a tuple of `past_key_values` is deprecated and will be removed in Transformers v4.58.0. "
	"You should pass an instance of `Cache` instead."
	)
	model_kwargs[cache_name] = (
	DynamicCache.from_legacy_cache(user_defined_cache)
	if not requires_cross_attention_cache
	else EncoderDecoderCache.from_legacy_cache(user_defined_cache)
	)
	return

	# Quick escape route 2: if the user specifies no cache is to be used. (conflicting arguments are handled in
	# `generation_config.validate()`)
	if generation_config.use_cache is False:
	return

	# Quick escape route 3: model that only supports legacy caches or models that supply it in
	# `prepare_inputs_for_generation` (mamba, zamba, ...)
	if not self._supports_default_dynamic_cache():
	if generation_config.cache_implementation is not None:
	logger.warning_once(
	"This model does not support `Cache` instances. `cache_implementation` (set to "
	f"{generation_config.cache_implementation}) will be ignored.",
	)
	return

	# Otherwise we NEED to prepare a cache, based on `generation_config.cache_implementation`

	# TODO(joao): support static caches in assisted generation. assisted generation needs to roll back caches,
	# which is only supported in dynamic caches atm
	if (
	generation_mode == GenerationMode.ASSISTED_GENERATION
	and generation_config.cache_implementation is not None
	):
	logger.warning_once(
	"An assistant model is provided, using a dynamic cache instead of a cache of type="
	f"'{generation_config.cache_implementation}'."
	)
	generation_config.cache_implementation = None

	# Assisted decoding and contrastive search require cache rollback, which is incompatible with sliding layers.
	# To handle this, we skip passing the model config to DynamicCache (forcing a full-layer cache).
	# The "dynamic_full" option is a shortcut for generate() users to avoid sliding layers on their own.
	if (
	generation_mode in (GenerationMode.ASSISTED_GENERATION, GenerationMode.CONTRASTIVE_SEARCH)
	or generation_config.cache_implementation == "dynamic_full"
	):
	dynamic_cache_kwargs = {}
	else:
	dynamic_cache_kwargs = {"config": self.config.get_text_config(decoder=True)}
	if generation_config.cache_implementation is not None:
	if generation_config.cache_implementation in ALL_STATIC_CACHE_IMPLEMENTATIONS:
	if generation_config.cache_implementation in DEPRECATED_STATIC_CACHE_IMPLEMENTATIONS:
	logger.warning_once(
	f"Using `cache_implementation='{generation_config.cache_implementation}' is deprecated. "
	f"Please only use one of {STATIC_CACHE_IMPLEMENTATIONS}, and the layer structure will be "
	"inferred automatically."
	)
	model_kwargs[cache_name] = self._get_cache(
	cache_implementation=generation_config.cache_implementation,
	batch_size=max(generation_config.num_beams, generation_config.num_return_sequences) * batch_size,
	max_cache_len=max_cache_length,
	model_kwargs=model_kwargs,
	)
	elif generation_config.cache_implementation == "quantized":
	if self.config.is_encoder_decoder or not self._supports_default_dynamic_cache():
	raise ValueError(
	"This model does not support the quantized cache. If you want your model to support quantized "
	"cache, please open an issue and tag @zucchini-nlp."
	)

	cache_config = generation_config.cache_config if generation_config.cache_config is not None else {}
	# Add the config if it was not provided, as it's a required argument
	if "config" not in cache_config:
	cache_config["config"] = self.config.get_text_config()
	# Pop the backend from the config (defaults to quanto if not defined)
	backend = cache_config.pop("backend", "quanto")

	if backend == "quanto" and not is_optimum_quanto_available():
	raise ImportError(
	"You need to install optimum-quanto in order to use KV cache quantization with optimum-quanto "
	"backend. Please install it via with `pip install optimum-quanto`"
	)
	elif backend == "HQQ" and not is_hqq_available():
	raise ImportError(
	"You need to install `HQQ` in order to use KV cache quantization with HQQ backend. "
	"Please install it via with `pip install hqq`"
	)
	model_kwargs[cache_name] = QuantizedCache(backend=backend, **cache_config)
	elif generation_config.cache_implementation == "offloaded":
	model_kwargs[cache_name] = DynamicCache(**dynamic_cache_kwargs, offloading=True)
	elif "dynamic" in generation_config.cache_implementation:
	model_kwargs[cache_name] = DynamicCache(**dynamic_cache_kwargs)

	# Use DynamicCache instance by default. This will avoid back and forth from legacy format that
	# keeps copying the cache thus using much more memory
	# TODO (joao): remove this `else` when we remove the last traces of the legacy cache format (v4.58.0, search
	# for `instance(past_key_values, Cache)` as well). In general, if `cache_implementation` is unset, cache
	# initialization should happen inside the model at prefill time.
	else:
	model_kwargs[cache_name] = DynamicCache(**dynamic_cache_kwargs)

	# TODO (joao): this logic is incomplete, e.g. `offloaded` should apply to both caches. Refactor this function
	# to correctly pass parameterization to both caches.
	if requires_cross_attention_cache and not isinstance(model_kwargs[cache_name], EncoderDecoderCache):
	model_kwargs[cache_name] = EncoderDecoderCache(
	model_kwargs[cache_name], # self-attention cache
	DynamicCache(**dynamic_cache_kwargs), # cross-attention cache
	)

	def _supports_logits_to_keep(self) -> bool:
	"""
	Return True if the current model supports the keyword argument `logits_to_keep` in forward()
	to save memory. Checking it in this way allows to avoid using a new model attribute.
	"""
	return "logits_to_keep" in set(inspect.signature(self.forward).parameters.keys())

	def _prepare_special_tokens(
	self,
	generation_config: GenerationConfig,
	kwargs_has_attention_mask: Optional[bool] = None,
	device: Optional[Union[torch.device, str]] = None,
	):
	"""
	Prepares the special tokens for generation, overwriting the generation config with their processed versions
	converted to tensor.

	Note that `generation_config` is changed in place and stops being serializable after this method is called.
	That is no problem if called within `generate` (`generation_config` is a local copy that doesn't leave the
	function). However, if called outside `generate`, consider creating a copy of `generation_config` first.
	"""

	# Convert special tokens to tensors
	def _tensor_or_none(token, device=None):
	if token is None:
	return token

	device = device if device is not None else self.device
	if isinstance(token, torch.Tensor):
	return token.to(device)
	return torch.tensor(token, device=device, dtype=torch.long)

	bos_token_tensor = _tensor_or_none(generation_config.bos_token_id, device=device)
	eos_token_tensor = _tensor_or_none(generation_config.eos_token_id, device=device)
	pad_token_tensor = _tensor_or_none(generation_config.pad_token_id, device=device)
	decoder_start_token_tensor = _tensor_or_none(generation_config.decoder_start_token_id, device=device)

	# for BC we also try to get `decoder_start_token_id` or `bos_token_id` (#30892)
	if self.config.is_encoder_decoder:
	decoder_start_token_tensor = (
	decoder_start_token_tensor if decoder_start_token_tensor is not None else bos_token_tensor
	)

	# We can have more than one eos token. Always treat it as a 1D tensor (when it exists).
	if eos_token_tensor is not None and eos_token_tensor.ndim == 0:
	eos_token_tensor = eos_token_tensor.unsqueeze(0)

	# Set pad token if unset (and there are conditions to do so)
	if pad_token_tensor is None and eos_token_tensor is not None:
	if kwargs_has_attention_mask is not None and not kwargs_has_attention_mask:
	logger.warning(
	"The attention mask and the pad token id were not set. As a consequence, you may observe "
	"unexpected behavior. Please pass your input's `attention_mask` to obtain reliable results."
	)
	pad_token_tensor = eos_token_tensor[0]
	logger.warning(f"Setting `pad_token_id` to `eos_token_id`:{pad_token_tensor} for open-end generation.")

	# Sanity checks/warnings
	if self.config.is_encoder_decoder and decoder_start_token_tensor is None:
	raise ValueError(
	"`decoder_start_token_id` or `bos_token_id` has to be defined for encoder-decoder generation."
	)
	if (
	eos_token_tensor is not None
	and isin_mps_friendly(elements=eos_token_tensor, test_elements=pad_token_tensor).any()
	):
	if kwargs_has_attention_mask is not None and not kwargs_has_attention_mask:
	logger.warning_once(
	"The attention mask is not set and cannot be inferred from input because pad token is same as "
	"eos token. As a consequence, you may observe unexpected behavior. Please pass your input's "
	"`attention_mask` to obtain reliable results."
	)
	if eos_token_tensor is not None and (
	torch.is_floating_point(eos_token_tensor) or (eos_token_tensor < 0).any()
	):
	logger.warning(
	f"`eos_token_id` should consist of positive integers, but is {eos_token_tensor}. Your generation "
	"will not stop until the maximum length is reached. Depending on other flags, it may even crash."
	)

	# Update generation config with the updated special tokens tensors
	# NOTE: this must be written into a different attribute name than the one holding the original special tokens
	# (in their non-tensor form), in order to enable end-to-end compilation. See
	# https://pytorch.org/docs/stable/torch.compiler_cudagraph_trees.html#limitations
	generation_config._bos_token_tensor = bos_token_tensor
	generation_config._eos_token_tensor = eos_token_tensor
	generation_config._pad_token_tensor = pad_token_tensor
	generation_config._decoder_start_token_tensor = decoder_start_token_tensor

	def _valid_auto_compile_criteria(self, model_kwargs: dict[str, Any], generation_config: GenerationConfig) -> bool:
	"""
	Determines whether to trigger auto-compilation of the model's forward pass at generation time.
	"""
	# Override: honor `disable_compile` flag
	if generation_config.disable_compile:
	return False

	# Base logic
	valid_hardware = self.device.type == "cuda" or bool(
	generation_config.compile_config is not None and generation_config.compile_config._compile_all_devices
	)
	using_compilable_cache = (
	isinstance(model_kwargs.get("past_key_values"), Cache) and model_kwargs["past_key_values"].is_compileable
	)
	can_compile = valid_hardware and using_compilable_cache

	# Exception 1: Some quantization methods do not support compilation
	if getattr(self, "hf_quantizer", None) is not None:
	can_compile &= self.hf_quantizer.is_compileable

	if hasattr(self, "hf_device_map"):
	all_model_devices = set(self.hf_device_map.values())
	# Exception 2: Don't compile if the model is using CPU offload (as of April 2025, this results in a crash)
	has_cpu_offload = "cpu" in all_model_devices and len(all_model_devices) > 1
	can_compile &= not has_cpu_offload

	# Exception 3: Disk offload is not supported for compilation
	has_disk_offload = "disk" in all_model_devices
	can_compile &= not has_disk_offload

	# Finally: if the user has manually specified compilation options, but compilation is not possible, let's warn
	# them
	if generation_config.compile_config is not None and not can_compile:
	logger.warning_once(
	"You have set `compile_config`, but we are unable to meet the criteria for compilation. Compilation "
	"will be skipped."
	)

	return can_compile

	def _get_deprecated_gen_repo(
	self,
	generation_mode: GenerationMode,
	trust_remote_code: bool,
	custom_generate: Optional[str] = None,
	) -> Optional[str]:
	"""
	Returns the Hub repo for a deprecated generation mode, if any.
	"""
	if custom_generate is not None or "/" not in (repo := GENERATION_MODES_MAPPING[generation_mode]):
	return None

	logger.warning_once(
	f"{generation_mode.name.replace('_', ' ').title()} was moved to a `custom_generate` repo: https://hf.co/{repo}. "
	f"To prevent loss of backward compatibility, add `custom_generate='{repo}'` "
	"to your `generate` call before v4.62.0."
	)
	if not trust_remote_code:
	raise ValueError(
	f"{generation_mode.name.replace('_', ' ').title()} requires `trust_remote_code=True` in your `generate` call, "
	f"since it loads https://hf.co/{repo}."
	)
	return repo

	def _extract_generation_mode_kwargs(
	self,
	custom_generate,
	kwargs,
	synced_gpus,
	assistant_model,
	streamer,
	) -> dict[str, Any]:
	"""
	Extracts and returns the generation mode related keyword arguments from the provided kwargs.
	"""
	generation_mode_kwargs = {
	"tokenizer": kwargs.pop("tokenizer", None),
	"assistant_tokenizer": kwargs.pop("assistant_tokenizer", None),
	"assistant_model": assistant_model,
	"streamer": streamer,
	}
	generation_mode_kwargs["synced_gpus"] = (
	(is_deepspeed_zero3_enabled() or is_fsdp_managed_module(self)) and dist.get_world_size() > 1
	if synced_gpus is None
	else synced_gpus
	)
	generation_mode_kwargs = {k: v for k, v in generation_mode_kwargs.items() if v is not None}
	# Custom_generate callables can have their own set of arguments
	# To extract them, we compare the signature with the standard _sample method
	if isinstance(custom_generate, Callable):
	usual_mode_kwargs = inspect.signature(GenerationMixin._sample).parameters.keys()
	custom_generate_kwargs = inspect.signature(custom_generate).parameters.keys()
	new_custom_keys = custom_generate_kwargs - usual_mode_kwargs
	generation_mode_kwargs = {k: kwargs.pop(k) for k in new_custom_keys if k in kwargs}
	return generation_mode_kwargs

	@torch.no_grad()
	def generate(
	self,
	inputs: Optional[torch.Tensor] = None,
	generation_config: Optional[GenerationConfig] = None,
	logits_processor: Optional[LogitsProcessorList] = None,
	stopping_criteria: Optional[StoppingCriteriaList] = None,
	prefix_allowed_tokens_fn: Optional[Callable[[int, torch.Tensor], list[int]]] = None,
	synced_gpus: Optional[bool] = None,
	assistant_model: Optional["PreTrainedModel"] = None,
	streamer: Optional["BaseStreamer"] = None,
	negative_prompt_ids: Optional[torch.Tensor] = None,
	negative_prompt_attention_mask: Optional[torch.Tensor] = None,
	use_model_defaults: Optional[bool] = None,
	custom_generate: Optional[Union[str, Callable]] = None,
	**kwargs,
	) -> Union[GenerateOutput, torch.LongTensor]:
	r"""

	Generates sequences of token ids for models with a language modeling head.

	<Tip warning={true}>

	Most generation-controlling parameters are set in `generation_config` which, if not passed, will be set to the
	model's default generation configuration. You can override any `generation_config` by passing the corresponding
	parameters to generate(), e.g. `.generate(inputs, num_beams=4, do_sample=True)`.

	For an overview of generation strategies and code examples, check out the [following
	guide](../generation_strategies).

	</Tip>

	Parameters:
	inputs (`torch.Tensor` of varying shape depending on the modality, optional):
	The sequence used as a prompt for the generation or as model inputs to the encoder. If `None` the
	method initializes it with `bos_token_id` and a batch size of 1. For decoder-only models `inputs`
	should be in the format of `input_ids`. For encoder-decoder models inputs can represent any of
	`input_ids`, `input_values`, `input_features`, or `pixel_values`.
	generation_config ([`~generation.GenerationConfig`], optional):
	The generation configuration to be used as base parametrization for the generation call. `**kwargs`
	passed to generate matching the attributes of `generation_config` will override them. If
	`generation_config` is not provided, the default will be used, which has the following loading
	priority: 1) from the `generation_config.json` model file, if it exists; 2) from the model
	configuration. Please note that unspecified parameters will inherit [`~generation.GenerationConfig`]'s
	default values, whose documentation should be checked to parameterize generation.
	logits_processor (`LogitsProcessorList`, optional):
	Custom logits processors that complement the default logits processors built from arguments and
	generation config. If a logit processor is passed that is already created with the arguments or a
	generation config an error is thrown. This feature is intended for advanced users.
	stopping_criteria (`StoppingCriteriaList`, optional):
	Custom stopping criteria that complements the default stopping criteria built from arguments and a
	generation config. If a stopping criteria is passed that is already created with the arguments or a
	generation config an error is thrown. If your stopping criteria depends on the `scores` input, make
	sure you pass `return_dict_in_generate=True, output_scores=True` to `generate`. This feature is
	intended for advanced users.
	prefix_allowed_tokens_fn (`Callable[[int, torch.Tensor], list[int]]`, optional):
	If provided, this function constraints the beam search to allowed tokens only at each step. If not
	provided no constraint is applied. This function takes 2 arguments: the batch ID `batch_id` and
	`input_ids`. It has to return a list with the allowed tokens for the next generation step conditioned
	on the batch ID `batch_id` and the previously generated tokens `inputs_ids`. This argument is useful
	for constrained generation conditioned on the prefix, as described in [Autoregressive Entity
	Retrieval](https://huggingface.co/papers/2010.00904).
	synced_gpus (`bool`, optional):
	Whether to continue running the while loop until max_length. Unless overridden, this flag will be set
	to `True` if using `FullyShardedDataParallel` or DeepSpeed ZeRO Stage 3 with multiple GPUs to avoid
	deadlocking if one GPU finishes generating before other GPUs. Otherwise, defaults to `False`.
	assistant_model (`PreTrainedModel`, optional):
	An assistant model that can be used to accelerate generation. The assistant model must have the exact
	same tokenizer. The acceleration is achieved when forecasting candidate tokens with the assistant model
	is much faster than running generation with the model you're calling generate from. As such, the
	assistant model should be much smaller.
	streamer (`BaseStreamer`, optional):
	Streamer object that will be used to stream the generated sequences. Generated tokens are passed
	through `streamer.put(token_ids)` and the streamer is responsible for any further processing.
	negative_prompt_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`, optional):
	The negative prompt needed for some processors such as CFG. The batch size must match the input batch
	size. This is an experimental feature, subject to breaking API changes in future versions.
	negative_prompt_attention_mask (`torch.LongTensor` of shape `(batch_size, sequence_length)`, optional):
	Attention_mask for `negative_prompt_ids`.
	use_model_defaults (`bool`, optional):
	When it is `True`, unset parameters in `generation_config` will be set to the model-specific default
	generation configuration (`model.generation_config`), as opposed to the global defaults
	(`GenerationConfig()`). If unset, models saved starting from `v4.50` will consider this flag to be
	`True`.
	custom_generate (`str` or `Callable`, optional):
	One of the following:
	- `str` (Hugging Face Hub repository name): runs the custom `generate` function defined at
	`custom_generate/generate.py` in that repository instead of the standard `generate` method. The
	repository fully replaces the generation logic, and the return type may differ.
	- `str` (local repository path): same as above but from a local path, `trust_remote_code` not required.
	- `Callable`: `generate` will perform the usual input preparation steps, then call the provided callable to
	run the decoding loop.
	For more information, see [the docs](../../generation_strategies#custom-generation-methods).
	kwargs (`dict[str, Any]`, optional):
	Ad hoc parametrization of `generation_config` and/or additional model-specific kwargs that will be
	forwarded to the `forward` function of the model. If the model is an encoder-decoder model, encoder
	specific kwargs should not be prefixed and decoder specific kwargs should be prefixed with decoder_.

	Return:
	[`~utils.ModelOutput`] or `torch.LongTensor`: A [`~utils.ModelOutput`] (if `return_dict_in_generate=True`
	or when `config.return_dict_in_generate=True`) or a `torch.LongTensor`.

	If the model is not an encoder-decoder model (`model.config.is_encoder_decoder=False`), the possible
	[`~utils.ModelOutput`] types are:

	- [`~generation.GenerateDecoderOnlyOutput`],
	- [`~generation.GenerateBeamDecoderOnlyOutput`]

	If the model is an encoder-decoder model (`model.config.is_encoder_decoder=True`), the possible
	[`~utils.ModelOutput`] types are:

	- [`~generation.GenerateEncoderDecoderOutput`],
	- [`~generation.GenerateBeamEncoderDecoderOutput`]
	"""
	# 0. If requested, load an arbitrary generation recipe from the Hub and run it instead
	trust_remote_code = kwargs.pop("trust_remote_code", None)

	if custom_generate is not None and isinstance(custom_generate, str):
	# Get all `generate` arguments in a single variable. Custom functions are responsible for handling them:
	# they receive the same inputs as `generate`, with `model` instead of `self` and excluding the arguments to
	# trigger the custom generation. They can access to methods from `GenerationMixin` through `model`.
	global_keys_to_exclude = {
	"self",
	"kwargs",
	"global_keys_to_exclude",
	"trust_remote_code",
	"custom_generate",
	}
	generate_arguments = {key: value for key, value in locals().items() if key not in global_keys_to_exclude}
	generate_arguments.update(kwargs)

	custom_generate_function = self.load_custom_generate(
	custom_generate, trust_remote_code=trust_remote_code, **kwargs
	)
	return custom_generate_function(model=self, **generate_arguments)

	# 1. Handle kwargs, `generation_config`, validate them and obtain generation mode
	generation_mode_kwargs = self._extract_generation_mode_kwargs(
	custom_generate,
	kwargs,
	synced_gpus,
	assistant_model,
	streamer,
	)

	generation_config, model_kwargs = self._prepare_generation_config(
	generation_config, use_model_defaults, **kwargs
	)
	generation_mode = generation_config.get_generation_mode(assistant_model)
	if isinstance(custom_generate, Callable):
	decoding_method = custom_generate
	else:
	# type() required to access the unbound class-level method
	decoding_method = getattr(type(self), GENERATION_MODES_MAPPING[generation_mode])

	self._validate_model_kwargs(model_kwargs.copy())
	self._validate_generation_mode(generation_mode, generation_config, generation_mode_kwargs)

	# Deprecation-related step: set Hub repo for deprecated strategies.
	# NOTE: This must come after initializing generation_config, since we need it to determine if this is a deprecated mode.
	# It must also be before any preparation steps, since Hub repos expect to be loaded before preparation steps.
	# TODO joao, manuel: remove this in v4.62.0
	if deprecated_mode_repo := self._get_deprecated_gen_repo(generation_mode, trust_remote_code, custom_generate):
	return GenerationMixin.generate(
	self,
	inputs=inputs,
	generation_config=generation_config,
	logits_processor=logits_processor,
	stopping_criteria=stopping_criteria,
	prefix_allowed_tokens_fn=prefix_allowed_tokens_fn,
	assistant_model=assistant_model,
	negative_prompt_ids=negative_prompt_ids,
	negative_prompt_attention_mask=negative_prompt_attention_mask,
	use_model_defaults=use_model_defaults,
	custom_generate=deprecated_mode_repo,
	trust_remote_code=trust_remote_code,
	**generation_mode_kwargs,
	**kwargs,
	)

	# 2. Set generation parameters if not already defined
	logits_processor = logits_processor if logits_processor is not None else LogitsProcessorList()
	stopping_criteria = stopping_criteria if stopping_criteria is not None else StoppingCriteriaList()

	accepts_attention_mask = "attention_mask" in set(inspect.signature(self.forward).parameters.keys())
	requires_attention_mask = "encoder_outputs" not in model_kwargs
	kwargs_has_attention_mask = model_kwargs.get("attention_mask", None) is not None

	# 3. Define model inputs
	inputs_tensor, model_input_name, model_kwargs = self._prepare_model_inputs(
	inputs, generation_config.bos_token_id, model_kwargs
	)
	# Some generation modes (e.g. assisted) need `inputs_tensor` to rerun encoder.forward()
	if "inputs_tensor" in inspect.signature(decoding_method).parameters.keys():
	generation_mode_kwargs["inputs_tensor"] = inputs_tensor
	batch_size = inputs_tensor.shape[0]

	device = inputs_tensor.device
	self._prepare_special_tokens(generation_config, kwargs_has_attention_mask, device=device)

	# decoder-only models must use left-padding for batched generation.
	if not self.config.is_encoder_decoder:
	# If `input_ids` was given, check if the last id in any sequence is `pad_token_id`
	# Note: If using, `inputs_embeds` this check does not work, because we want to be more hands-off.
	if (
	generation_config._pad_token_tensor is not None
	and batch_size > 1
	and len(inputs_tensor.shape) == 2
	and torch.sum(inputs_tensor[:, -1] == generation_config._pad_token_tensor) > 0
	):
	logger.warning(
	"A decoder-only architecture is being used, but right-padding was detected! For correct "
	"generation results, please set `padding_side='left'` when initializing the tokenizer."
	)

	# 4. Define other model kwargs
	# decoder-only models with inputs_embeds forwarding must use caching (otherwise we can't detect whether we are
	# generating the first new token or not, and we only want to use the embeddings for the first new token)
	if not self.config.is_encoder_decoder and model_input_name == "inputs_embeds":
	generation_config.use_cache = True

	if not kwargs_has_attention_mask and requires_attention_mask and accepts_attention_mask:
	model_kwargs["attention_mask"] = self._prepare_attention_mask_for_generation(
	inputs_tensor, generation_config, model_kwargs
	)
	elif kwargs_has_attention_mask:
	# TODO (joao): generalize this check with other types of inputs
	if model_input_name == "input_ids" and len(model_kwargs["attention_mask"].shape) > 2:
	raise ValueError("`attention_mask` passed to `generate` must be 2D.")

	if self.config.is_encoder_decoder and "encoder_outputs" not in model_kwargs:
	# if model is encoder decoder encoder_outputs are created and added to `model_kwargs`
	model_kwargs = self._prepare_encoder_decoder_kwargs_for_generation(
	inputs_tensor, model_kwargs, model_input_name, generation_config
	)

	# 5. Prepare `input_ids` which will be used for auto-regressive generation
	if self.config.is_encoder_decoder:
	input_ids, model_kwargs = self._prepare_decoder_input_ids_for_generation(
	batch_size=batch_size,
	model_input_name=model_input_name,
	model_kwargs=model_kwargs,
	decoder_start_token_id=generation_config._decoder_start_token_tensor,
	device=inputs_tensor.device,
	)
	else:
	input_ids = inputs_tensor if model_input_name == "input_ids" else model_kwargs.pop("input_ids")

	# Expand inputs depending on the generation mode
	input_ids, model_kwargs = self._expand_inputs_for_generation(
	input_ids=input_ids,
	expand_size=max(generation_config.num_beams, generation_config.num_return_sequences),
	is_encoder_decoder=self.config.is_encoder_decoder,
	**model_kwargs,
	)

	if generation_config.token_healing:
	input_ids = self.heal_tokens(input_ids, generation_mode_kwargs.get("tokenizer"))

	if streamer is not None:
	streamer.put(input_ids.cpu())

	# 6. Prepare `max_length` depending on other stopping criteria.
	input_ids_length = input_ids.shape[1]
	has_default_max_length = kwargs.get("max_length") is None and generation_config.max_length is not None
	has_default_min_length = kwargs.get("min_length") is None and generation_config.min_length is not None
	generation_config = self._prepare_generated_length(
	generation_config=generation_config,
	has_default_max_length=has_default_max_length,
	has_default_min_length=has_default_min_length,
	model_input_name=model_input_name,
	inputs_tensor=inputs_tensor,
	input_ids_length=input_ids_length,
	)

	# If the model supports `logits_to_keep` in forward(), set it to 1 to avoid computing the whole
	# logit matrix. This can save a lot of memory during the first forward pass. Note that assisted decoding
	# dynamically overrides this value as it can need more than the last token logits
	if self._supports_logits_to_keep() and "logits_to_keep" not in model_kwargs:
	model_kwargs["logits_to_keep"] = 1

	self._validate_generated_length(generation_config, input_ids_length, has_default_max_length)

	# 7. Prepare the cache.
	# - `model_kwargs` may be updated in place with a cache as defined by the parameters in `generation_config`.
	# - different models have a different cache name expected by the model (default = "past_key_values")
	# - `max_length`, prepared above, is used to determine the maximum cache length
	max_cache_length = generation_config.max_length - 1
	if (
	inputs_tensor.shape[1] != input_ids_length
	and model_input_name == "inputs_embeds"
	and not self.config.is_encoder_decoder
	):
	max_cache_length += inputs_tensor.shape[1]
	self._prepare_cache_for_generation(
	generation_config, model_kwargs, generation_mode, batch_size, max_cache_length
	)

	if self.device.type != input_ids.device.type:
	warnings.warn(
	"You are calling .generate() with the `input_ids` being on a device type different"
	f" than your model's device. `input_ids` is on {input_ids.device.type}, whereas the model"
	f" is on {self.device.type}. You may experience unexpected behaviors or slower generation."
	" Please make sure that you have put `input_ids` to the"
	f" correct device by calling for example input_ids = input_ids.to('{self.device.type}') before"
	" running `.generate()`.",
	UserWarning,
	)

	# 8. prepare logits processors and stopping criteria
	prepared_logits_processor = self._get_logits_processor(
	generation_config=generation_config,
	input_ids_seq_length=input_ids_length,
	encoder_input_ids=inputs_tensor,
	prefix_allowed_tokens_fn=prefix_allowed_tokens_fn,
	logits_processor=logits_processor,
	device=inputs_tensor.device,
	model_kwargs=model_kwargs,
	negative_prompt_ids=negative_prompt_ids,
	negative_prompt_attention_mask=negative_prompt_attention_mask,
	)
	prepared_stopping_criteria = self._get_stopping_criteria(
	generation_config=generation_config,
	stopping_criteria=stopping_criteria,
	tokenizer=generation_mode_kwargs.get("tokenizer"),
	)

	# Set model_kwargs `use_cache` so we can use it later in forward runs
	model_kwargs["use_cache"] = generation_config.use_cache

	# 9. Call generation mode
	result = decoding_method(
	self,
	input_ids,
	logits_processor=prepared_logits_processor,
	stopping_criteria=prepared_stopping_criteria,
	generation_config=generation_config,
	**generation_mode_kwargs,
	**model_kwargs,
	)

	# Convert to legacy cache format if requested
	if (
	generation_config.return_legacy_cache is True
	and hasattr(result, "past_key_values")
	and getattr(result.past_key_values, "to_legacy_cache") is not None
	):
	result.past_key_values = result.past_key_values.to_legacy_cache()
	return result

	def _has_unfinished_sequences(self, this_peer_finished: bool, synced_gpus: bool, device: torch.device) -> bool:
	"""
	Returns whether there are still unfinished sequences in the device. The existence of unfinished sequences is
	fed through `this_peer_finished`. ZeRO stage 3-friendly.
	"""
	if synced_gpus:
	# Under synced_gpus the `forward` call must continue until all gpus complete their sequence.
	# The following logic allows an early break if all peers finished generating their sequence
	this_peer_finished_flag = torch.tensor(0.0 if this_peer_finished else 1.0, device=device)
	# send 0.0 if we finished, 1.0 otherwise
	dist.all_reduce(this_peer_finished_flag, op=dist.ReduceOp.SUM)
	# did all peers finish? the reduced sum will be 0.0 then
	if this_peer_finished_flag.item() == 0.0:
	return False
	elif this_peer_finished:
	return False
	return True

	def heal_tokens(
	self, input_ids: torch.LongTensor, tokenizer: Optional["PreTrainedTokenizerBase"] = None
	) -> torch.LongTensor:
	r"""
	Generates sequences of token ids for models with a language modeling head.
	Parameters:
	input_ids (`torch.LongTensor`): The sequence used as a prompt for the generation.
	tokenizer (`PreTrainedTokenizerBase`, optional): The tokenizer used to decode the input ids.
	Return:
	`torch.LongTensor` where each sequence has its tail token replaced with its appropriate extension.
	"""
	if tokenizer is None:
	raise ValueError(
	" When generating with token healing, you must pass the model's tokenizer to the `tokenizer` "
	"argument of `generate`."
	)

	bos_token_id, pad_token_id = tokenizer.bos_token_id, tokenizer.pad_token_id
	vocab_trie = ExtensionsTrie(tokenizer.get_vocab())
	generation_config = GenerationConfig(max_new_tokens=1, pad_token_id=pad_token_id)

	# assumption: leading/trailing whitespace is not meaningful, so the prompts are
	# stripped before re-tokenizing to desensitize generation to whitespace artefacts
	prompts = [p.strip() for p in tokenizer.batch_decode(input_ids, skip_special_tokens=True)]
	input_ids = tokenizer(
	prompts,
	return_tensors="pt",
	padding=True,
	).input_ids.to(input_ids.device)

	# replace bos with pad to not condition healing on it
	input_ids = torch.where(input_ids == bos_token_id, pad_token_id, input_ids)

	# the latter code assumes the input_ids is not empty, input_id has to be checked if contains elements
	if input_ids.numel() == 0:
	return input_ids

	tail_ids = input_ids[:, -1].tolist()

	# tail tokens are used for a prefix search, thus, whitespaces are replaced with
	# their tokenization (e.g. 'Ġ') to enable search for tokens prefixed with a whitespace
	if tokenizer.convert_tokens_to_ids(" ") is not None:
	space_tok = tokenizer.convert_ids_to_tokens(tokenizer.convert_tokens_to_ids(" "))[0]
	tail_toks = (tokenizer.decode(t).replace(" ", space_tok) for t in tail_ids)
	else:
	tail_toks = (tokenizer.decode(t) for t in tail_ids)

	for batch_idx, (tail_id, tail_tok) in enumerate(zip(tail_ids, tail_toks)):
	batch_ids = input_ids[batch_idx]
	if torch.all(batch_ids == pad_token_id).item():
	continue # skip empty sequences (all pad ids)

	# apply bias for alternatives (extensions) to the tail token
	"""
	seq_bias key has to be tuple with int so have to use
	tokenizer function to convert str to int
	"""
	seq_bias = {
	(tokenizer.convert_tokens_to_ids(alt_tok),): 10.0 for alt_tok in vocab_trie.extensions(prefix=tail_tok)
	}

	if len(seq_bias) == 1:
	continue # skip if there are no token alternatives to heal with

	# slightly favor original token to limit aggressive healing e.g. 'http' -> 'https'
	seq_bias[(tail_id,)] += 1.0
	generation_config.update(sequence_bias=seq_bias)

	trimmed_ids = batch_ids[:-1]

	"""
	the latter code assumes trimmed_ids is not empty
	so have to check the its element count
	"""
	if trimmed_ids.numel() == 0:
	continue

	# if the prompt is a single (non-pad) token, regenerate from bos
	if len(batch_ids[batch_ids != pad_token_id]) == 1:
	trimmed_ids[-1] = bos_token_id

	input_ids[batch_idx] = self.generate(trimmed_ids.unsqueeze(0), generation_config=generation_config)

	return input_ids

	def _sample(
	self,
	input_ids: torch.LongTensor,
	logits_processor: LogitsProcessorList,
	stopping_criteria: StoppingCriteriaList,
	generation_config: GenerationConfig,
	synced_gpus: bool = False,
	streamer: Optional["BaseStreamer"] = None,
	**model_kwargs,
	) -> Union[GenerateNonBeamOutput, torch.LongTensor]:
	r"""
	Generates sequences of token ids for models with a language modeling head using multinomial sampling and
	can be used for text-decoder, text-to-text, speech-to-text, and vision-to-text models.

	Parameters:
	input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`):
	The sequence used as a prompt for the generation.
	logits_processor (`LogitsProcessorList`):
	An instance of [`LogitsProcessorList`]. List of instances of class derived from [`LogitsProcessor`]
	used to modify the prediction scores of the language modeling head applied at each generation step.
	stopping_criteria (`StoppingCriteriaList`):
	An instance of [`StoppingCriteriaList`]. List of instances of class derived from [`StoppingCriteria`]
	used to tell if the generation loop should stop.
	generation_config ([`~generation.GenerationConfig`]):
	The generation configuration to be used as parametrization of the decoding method.
	synced_gpus (`bool`):
	Whether to continue running the while loop until max_length (needed to avoid deadlocking with
	`FullyShardedDataParallel` and DeepSpeed ZeRO Stage 3).
	streamer (`BaseStreamer`, optional):
	Streamer object that will be used to stream the generated sequences. Generated tokens are passed
	through `streamer.put(token_ids)` and the streamer is responsible for any further processing.
	model_kwargs:
	Additional model specific kwargs will be forwarded to the `forward` function of the model. If model is
	an encoder-decoder model the kwargs should include `encoder_outputs`.

	Return:
	[`~generation.GenerateDecoderOnlyOutput`], [`~generation.GenerateEncoderDecoderOutput`] or `torch.LongTensor`:
	A `torch.LongTensor` containing the generated tokens (default behaviour) or a
	[`~generation.GenerateDecoderOnlyOutput`] if `model.config.is_encoder_decoder=False` and
	`return_dict_in_generate=True` or a [`~generation.GenerateEncoderDecoderOutput`] if
	`model.config.is_encoder_decoder=True`.
	"""
	# init values
	pad_token_id = generation_config._pad_token_tensor
	output_attentions = generation_config.output_attentions
	output_hidden_states = generation_config.output_hidden_states
	output_scores = generation_config.output_scores
	output_logits = generation_config.output_logits
	return_dict_in_generate = generation_config.return_dict_in_generate
	has_eos_stopping_criteria = any(hasattr(criteria, "eos_token_id") for criteria in stopping_criteria)
	do_sample = generation_config.do_sample

	# init attention / hidden states / scores tuples
	scores = () if (return_dict_in_generate and output_scores) else None
	raw_logits = () if (return_dict_in_generate and output_logits) else None
	decoder_attentions = () if (return_dict_in_generate and output_attentions) else None
	cross_attentions = () if (return_dict_in_generate and output_attentions) else None
	decoder_hidden_states = () if (return_dict_in_generate and output_hidden_states) else None

	# if model is an encoder-decoder, retrieve encoder attention weights and hidden states
	if return_dict_in_generate and self.config.is_encoder_decoder:
	encoder_attentions = model_kwargs["encoder_outputs"].get("attentions") if output_attentions else None
	encoder_hidden_states = (
	model_kwargs["encoder_outputs"].get("hidden_states") if output_hidden_states else None
	)

	# keep track of which sequences are already finished
	batch_size, cur_len = input_ids.shape[:2]
	this_peer_finished = False
	unfinished_sequences = torch.ones(batch_size, dtype=torch.long, device=input_ids.device)
	model_kwargs = self._get_initial_cache_position(cur_len, input_ids.device, model_kwargs)

	model_forward = self.__call__
	compile_forward = self._valid_auto_compile_criteria(model_kwargs, generation_config)
	if compile_forward:
	os.environ["TOKENIZERS_PARALLELISM"] = "0"
	# If we use FA2 and a static cache, we cannot compile with fullgraph
	if self.config._attn_implementation == "flash_attention_2":
	# only raise warning if the user passed an explicit compile-config
	if generation_config.compile_config is not None and generation_config.compile_config.fullgraph:
	logger.warning_once(
	"When using Flash Attention 2 and a static cache, you cannot use the option `CompileConfig(fullgraph=True)` as "
	"FA2 introduces graph breaks. We overrode the option with `fullgraph=False`."
	)
	generation_config.compile_config.fullgraph = False
	model_forward = self.get_compiled_call(generation_config.compile_config)

	if generation_config.prefill_chunk_size is not None:
	model_kwargs = self._prefill_chunking(input_ids, generation_config, **model_kwargs)
	is_prefill = False
	else:
	is_prefill = True

	while self._has_unfinished_sequences(this_peer_finished, synced_gpus, device=input_ids.device):
	# prepare model inputs
	model_inputs = self.prepare_inputs_for_generation(input_ids, **model_kwargs)

	if is_prefill:
	outputs = self(**model_inputs, return_dict=True)
	is_prefill = False
	else:
	outputs = model_forward(**model_inputs, return_dict=True)

	# synced_gpus: don't waste resources running the code we don't need; kwargs must be updated before skipping
	model_kwargs = self._update_model_kwargs_for_generation(
	outputs,
	model_kwargs,
	is_encoder_decoder=self.config.is_encoder_decoder,
	)
	if synced_gpus and this_peer_finished:
	continue

	# Copy is needed to avoid keeping a hanging ref to outputs.logits which may be very large for first iteration
	# (the clone itself is always small)
	next_token_logits = outputs.logits[:, -1, :].to(copy=True, dtype=torch.float32, device=input_ids.device)

	# pre-process distribution
	next_token_scores = logits_processor(input_ids, next_token_logits)

	# Store scores, attentions and hidden_states when required
	if return_dict_in_generate:
	if output_scores:
	scores += (next_token_scores,)
	if output_logits:
	raw_logits += (next_token_logits,)
	if output_attentions:
	decoder_attentions += (
	(outputs.decoder_attentions,) if self.config.is_encoder_decoder else (outputs.attentions,)
	)
	if self.config.is_encoder_decoder:
	cross_attentions += (outputs.cross_attentions,)

	if output_hidden_states:
	decoder_hidden_states += (
	(outputs.decoder_hidden_states,)
	if self.config.is_encoder_decoder
	else (outputs.hidden_states,)
	)

	# token selection
	if do_sample:
	probs = nn.functional.softmax(next_token_scores, dim=-1)
	# TODO (joao): this OP throws "skipping cudagraphs due to ['incompatible ops']", find solution
	next_tokens = torch.multinomial(probs, num_samples=1).squeeze(1)
	else:
	next_tokens = torch.argmax(next_token_scores, dim=-1)

	# finished sentences should have their next token be a padding token
	if has_eos_stopping_criteria:
	next_tokens = next_tokens * unfinished_sequences + pad_token_id * (1 - unfinished_sequences)

	# update generated ids, model inputs, and length for next step
	input_ids = torch.cat([input_ids, next_tokens[:, None]], dim=-1)
	if streamer is not None:
	streamer.put(next_tokens.cpu())

	unfinished_sequences = unfinished_sequences & ~stopping_criteria(input_ids, scores)
	this_peer_finished = unfinished_sequences.max() == 0
	cur_len += 1

	# This is needed to properly delete outputs.logits which may be very large for first iteration
	# Otherwise a reference to outputs is kept which keeps the logits alive in the next iteration
	del outputs

	if streamer is not None:
	streamer.end()

	if return_dict_in_generate:
	if self.config.is_encoder_decoder:
	return GenerateEncoderDecoderOutput(
	sequences=input_ids,
	scores=scores,
	logits=raw_logits,
	encoder_attentions=encoder_attentions,
	encoder_hidden_states=encoder_hidden_states,
	decoder_attentions=decoder_attentions,
	cross_attentions=cross_attentions,
	decoder_hidden_states=decoder_hidden_states,
	past_key_values=model_kwargs.get("past_key_values"),
	)
	else:
	return GenerateDecoderOnlyOutput(
	sequences=input_ids,
	scores=scores,
	logits=raw_logits,
	attentions=decoder_attentions,
	hidden_states=decoder_hidden_states,
	past_key_values=model_kwargs.get("past_key_values"),
	)
	else:
	return input_ids

	@staticmethod
	def _flatten_beam_dim(tensor: torch.Tensor) -> torch.Tensor:
	"""[batch_size, num_beams, ...] -> [batch_size * num_beams, ...]"""
	shape = list(tensor.shape)
	return torch.reshape(tensor, [shape[0] * shape[1]] + shape[2:])

	@staticmethod
	def _unflatten_beam_dim(tensor: torch.Tensor, batch_size: int, num_beams: int) -> torch.Tensor:
	"""[batch_size * num_beams, ...] -> [batch_size, num_beams, ...]"""
	shape = list(tensor.shape)
	return torch.reshape(tensor, [batch_size, num_beams] + shape[1:])

	@staticmethod
	def _gather_beams(tensor: torch.Tensor, beam_indices: torch.Tensor) -> torch.Tensor:
	"""
	Gathers the beam slices indexed by beam_indices into new beam array.

	Args:
	tensor (`torch.Tensor`): A tensor containing data to be gathered. The tensor is a 2D or a 3D tensor
	with the two first dimensions depicting the batch and the beam dimensions.
	beam_indices (`torch.Tensor` of shape `(batch_size, num_beams_to_select)`): The indices of the beams to
	select .

	Returns:
	A tensor with the selected beams
	"""
	# `take_along_dim` requires its indices arg to have the same number of dims as `input`
	while len(beam_indices.shape) < len(tensor.shape):
	beam_indices = beam_indices.unsqueeze(-1)
	gathered_tensor = torch.take_along_dim(input=tensor, indices=beam_indices, dim=1)
	return gathered_tensor

	@staticmethod
	def _check_early_stop_heuristic(
	is_early_stop_heuristic_unsatisfied: torch.Tensor,
	running_beam_scores: torch.Tensor,
	beam_scores: torch.Tensor,
	is_sent_finished: torch.Tensor,
	cur_len: int,
	max_length: int,
	decoder_prompt_len: int,
	early_stopping: Union[bool, str],
	length_penalty: float,
	):
	"""
	Determine whether early stopping is possible by checking if the best possible score of running beams
	could still improve upon the finished ones.

	Mechanism:
	- Without a length penalty, beam scores typically decrease as more tokens are generated.
	So, if the best possible score from any running beam is already worse than the worst finished beam,
	we can safely stop early.
	- With a length penalty, scores may increase with longer sequences. In this case, we use heuristics
	to estimate the best possible score — though this estimate may not always be correct — and stop
	if no further improvement seems likely.

	We apply different heuristics depending on the value of `early_stopping`:
	1. `early_stopping == False`:
	-> Use a heuristic that assumes the best score comes from the current length minus the decoder prompt length.
	-> See detailed discussion: https://github.com/huggingface/transformers/pull/20901#issuecomment-1369845565

	2. `early_stopping == "never"`:
	-> Estimate the best score using either `max_length` or `cur_len`, depending on the sign of `length_penalty`.
	-> A positive length penalty favors longer sequences, so we use `max_length` in that case.

	NOTE: the canonical beam search implementation can be replicated with `early_stopping="never"` and
	`length_penalty=0.0`, which are NOT the default flags. The default behavior was empirically found to produce
	better sequences (prior to 2022), and changing it is BC breaking.
	"""
	if early_stopping == "never" and length_penalty > 0.0:
	best_hypothetical_length = max_length - decoder_prompt_len
	else:
	best_hypothetical_length = cur_len - decoder_prompt_len
	best_possible_running_score = running_beam_scores[:, :1] / (best_hypothetical_length**length_penalty)
	worst_finished_score = torch.where(is_sent_finished, torch.min(beam_scores, dim=1, keepdim=True)[0], -1.0e9)
	return is_early_stop_heuristic_unsatisfied & torch.any(
	best_possible_running_score > worst_finished_score, dim=-1, keepdim=True
	)

	@staticmethod
	def _beam_search_has_unfinished_sequences(
	is_early_stop_heuristic_unsatisfied: torch.Tensor,
	is_sent_finished: torch.Tensor,
	next_token_hits_stopping_criteria: torch.Tensor,
	early_stopping: Union[bool, str],
	):
	"""
	Beam Search stopping condition -- halts the generation loop if any of these conditions becomes False
	"""
	# a. Can the open beams improve the top completed scores?
	improvement_possible = torch.any(is_early_stop_heuristic_unsatisfied)

	# b. Is there still a beam without fully completed sequences? This is only relevant if early_stopping is
	# enabled, where we want to finish as soon as all beams have a completed sequence.
	exists_open_beam = ~(torch.all(is_sent_finished) & (early_stopping is True))

	# c. Have we hit a stopping criteria with all running sequences and have no way to continue? e.g. we have
	# reached `max_length``
	valid_continuations = ~torch.all(next_token_hits_stopping_criteria)

	return improvement_possible & exists_open_beam & valid_continuations

	def _get_top_k_continuations(
	self,
	accumulated_log_probs: torch.Tensor,
	running_sequences: torch.Tensor,
	running_beam_indices: torch.Tensor,
	cur_len: int,
	decoder_prompt_len: int,
	do_sample: bool,
	beams_to_keep: int,
	num_beams: int,
	vocab_size: int,
	batch_size: int,
	) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
	"""
	Get top-K continuations given the accumulated log probs on the next token.

	A few notes to understand what's going on:
	1. Each item in batch has `num_beams` * `vocab_size` candidate continuations. For each item, get the
	top K [K = (number of EOS tokens + 1) * `num_beams`] candidates with the highest accumulated
	log-probabilities, or sample them without replacement using the accumulated scores
	2. We gather the top K (as opposed to `num_beams`, or any number lower than K) here so that we have at
	least `num_beams` sequences remaining to continue the live beam search.
	3. Note that other stopping criteria might result in impossible to continue beams, i.e. all continuations
	selected in this step hit the stopping criteria.
	"""
	# TODO (joao): This function should take an optional beam scorer function, to manipulate the scores after
	# token selection. The function should be an argument exposed, so that custom scoring functions can be
	# defined.

	# Gather the top K scores from _all_ beams.
	if do_sample:
	topk_indices = torch.multinomial(
	nn.functional.softmax(accumulated_log_probs, dim=-1), num_samples=beams_to_keep
	)
	topk_log_probs = torch.gather(input=accumulated_log_probs, dim=1, index=topk_indices)
	else:
	topk_log_probs, topk_indices = torch.topk(accumulated_log_probs, k=beams_to_keep)

	# Gather K top beams, recover the beam index by floor division and token id by modulo division
	topk_current_beam_indices = topk_indices // vocab_size
	topk_running_beam_indices = self._gather_beams(running_beam_indices, topk_current_beam_indices)
	topk_running_sequences = self._gather_beams(running_sequences, topk_current_beam_indices)
	topk_ids = topk_indices % vocab_size

	# Update sequences for the K top-k new sequences.
	topk_running_sequences[:, :, cur_len] = topk_ids

	# we want to store the beam indices with batch information -> real beam index = beam index % num beams
	batch_offset = torch.arange(batch_size, device=topk_ids.device).view(-1, 1) * num_beams
	batch_modified_indices = topk_current_beam_indices + batch_offset
	topk_running_beam_indices[:, :, cur_len - decoder_prompt_len] = batch_modified_indices

	return topk_log_probs, topk_running_sequences, topk_running_beam_indices

	def _get_running_beams_for_next_iteration(
	self,
	topk_log_probs: torch.Tensor,
	topk_running_sequences: torch.Tensor,
	topk_running_beam_indices: torch.Tensor,
	next_token_hits_stopping_criteria: torch.Tensor,
	num_beams: int,
	) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
	"""
	Given the top-K continuations, their scores, and whether they hit a stopping criteria, select the
	best non-finished beams to continue beam search in the next iteration.
	"""
	# To prevent these just finished sequences from being used in subsequent iterations, set their log probs
	# to a very large negative value
	topk_running_log_probs = topk_log_probs + next_token_hits_stopping_criteria.to(torch.float32) * -1.0e9

	next_topk_indices = torch.topk(topk_running_log_probs, k=num_beams)[1]
	running_sequences = self._gather_beams(topk_running_sequences, next_topk_indices)
	running_beam_scores = self._gather_beams(topk_running_log_probs, next_topk_indices)
	running_beam_indices = self._gather_beams(topk_running_beam_indices, next_topk_indices)
	return running_sequences, running_beam_scores, running_beam_indices

	def _update_finished_beams(
	self,
	sequences: torch.Tensor,
	topk_running_sequences: torch.Tensor,
	beam_scores: torch.Tensor,
	topk_log_probs: torch.Tensor,
	beam_indices: torch.Tensor,
	topk_running_beam_indices: torch.Tensor,
	is_early_stop_heuristic_unsatisfied: torch.Tensor,
	is_sent_finished: torch.Tensor,
	next_token_hits_stopping_criteria: torch.Tensor,
	top_num_beam_mask: torch.Tensor,
	num_beams: int,
	cur_len: int,
	decoder_prompt_len: int,
	length_penalty: float,
	early_stopping: Union[bool, str],
	) -> tuple[torch.Tensor, torch.Tensor, torch.Tensor, torch.Tensor]:
	"""
	Updates the finished beams if (and only if) there are new completed sequences that have a higher score than
	the current finished sequences.
	"""
	# Only the top `num_beam` sequences can be considered for the final returned sequences. Remember: the
	# remaining sequences only exist as a backup to ensure that we have at least `num_beams` sequences to
	# continue.
	did_top_num_beams_just_finished = next_token_hits_stopping_criteria & top_num_beam_mask[None, :]

	# Further process topk logits for the finished beams
	# - add length penalty
	topk_log_probs = topk_log_probs / ((cur_len + 1 - decoder_prompt_len) ** length_penalty)
	# - make sure no scores can be added anymore if beam is full and early stopping is on
	beams_in_batch_are_full = torch.all(is_sent_finished, axis=-1, keepdims=True) & (early_stopping is True)
	topk_log_probs += beams_in_batch_are_full.to(torch.float32) * -1.0e9
	# - make sure no scores can be added anymore if improvement is not possible
	topk_log_probs += (~is_early_stop_heuristic_unsatisfied).to(torch.float32) * -1.0e9

	# - make sure still running sequences cannot be chosen as finalized beam
	topk_log_probs += (~did_top_num_beams_just_finished) * -1.0e9

	# Get finalized `num_beam` sequences for the next generation step -- combine the previous finalized
	# data with the new finalized sequences (if any, non-finalized sequences have a very large negative score
	# in this step), and keep the best `num_beams` sequences.
	merged_sequences = torch.cat((sequences, topk_running_sequences), dim=1)
	merged_scores = torch.cat((beam_scores, topk_log_probs), dim=1)
	merged_beam_indices = torch.cat((beam_indices, topk_running_beam_indices), dim=1)
	merged_is_sent_finished = torch.cat((is_sent_finished, did_top_num_beams_just_finished), dim=1)
	topk_merged_indices = torch.topk(merged_scores, k=num_beams)[1]
	sequences = self._gather_beams(merged_sequences, topk_merged_indices)
	beam_scores = self._gather_beams(merged_scores, topk_merged_indices)
	beam_indices = self._gather_beams(merged_beam_indices, topk_merged_indices)
	is_sent_finished = self._gather_beams(merged_is_sent_finished, topk_merged_indices)
	return sequences, beam_scores, beam_indices, is_sent_finished

	# end of auxiliary functions for beam search

	def _beam_search(
	self,
	input_ids: torch.LongTensor,
	logits_processor: LogitsProcessorList,
	stopping_criteria: StoppingCriteriaList,
	generation_config: GenerationConfig,
	synced_gpus: bool = False,
	**model_kwargs,
	) -> Union[GenerateBeamOutput, torch.LongTensor]:
	r"""
	Generates sequences of token ids for models with a language modeling head using beam search decoding and
	can be used for text-decoder, text-to-text, speech-to-text, and vision-to-text models.

	If it's the first time you're diving into Beam Search, we recommend you read the following blog post:
	https://huggingface.co/blog/how-to-generate (especially the beam search section).

	You can recompute the sequence scores from the individual scores using the `compute_transition_scores` function
	(https://huggingface.co/docs/transformers/main_classes/text_generation#transformers.GenerationMixin.compute_transition_scores)

	Parameters:
	input_ids (`torch.LongTensor` of shape `(batch_size*num_beams, sequence_length)`):
	The sequence used as a prompt for the generation.
	logits_processor (`LogitsProcessorList`):
	An instance of [`LogitsProcessorList`]. List of instances of class derived from [`LogitsProcessor`]
	used to modify the prediction scores of the language modeling head applied at each generation step.
	stopping_criteria (`StoppingCriteriaList`:
	An instance of [`StoppingCriteriaList`]. List of instances of class derived from [`StoppingCriteria`]
	used to tell if the generation loop should stop.
	generation_config ([`~generation.GenerationConfig`]):
	The generation configuration to be used as parametrization of the decoding method.
	synced_gpus (`bool`):
	Whether to continue running the while loop until max_length (needed to avoid deadlocking with
	`FullyShardedDataParallel` and DeepSpeed ZeRO Stage 3).
	model_kwargs:
	Additional model specific kwargs will be forwarded to the `forward` function of the model. If model is
	an encoder-decoder model the kwargs should include `encoder_outputs`.

	Return:
	[`generation.GenerateBeamDecoderOnlyOutput`], [`~generation.GenerateBeamEncoderDecoderOutput`] or
	`torch.LongTensor`: A `torch.LongTensor` containing the generated tokens (default behaviour) or a
	[`~generation.GenerateBeamDecoderOnlyOutput`] if `model.config.is_encoder_decoder=False` and
	`return_dict_in_generate=True` or a [`~generation.GenerateBeamEncoderDecoderOutput`] if
	`model.config.is_encoder_decoder=True`.
	"""

	# 1. init beam_search values
	pad_token_id = generation_config._pad_token_tensor
	eos_token_id = generation_config._eos_token_tensor
	output_attentions = generation_config.output_attentions
	output_hidden_states = generation_config.output_hidden_states
	output_scores = generation_config.output_scores
	output_logits = generation_config.output_logits
	return_dict_in_generate = generation_config.return_dict_in_generate
	do_sample = generation_config.do_sample
	early_stopping = generation_config.early_stopping
	length_penalty = generation_config.length_penalty
	max_length = generation_config.max_length
	num_beams = generation_config.num_beams
	num_return_sequences = generation_config.num_return_sequences

	batch_size_unflattened, cur_len = input_ids.shape[:2]
	batch_size = batch_size_unflattened // num_beams
	# TODO (joao): standardize special cases
	if self.__class__.__name__ == "MoshiDepthDecoder":
	vocab_size = self.config.audio_vocab_size
	elif self.__class__.__name__ == "ImageGPTForCausalImageModeling":
	vocab_size = self.get_output_embeddings().out_features
	elif self.__class__.__name__ == "BarkSemanticModel":
	vocab_size = self.config.output_vocab_size
	else:
	vocab_size = self.config.get_text_config().vocab_size
	decoder_prompt_len = cur_len
	this_peer_finished = False

	# At each beam search step, we want to keep top K [K = (number of EOS tokens + 1) * `num_beams`] candidates
	# with the highest log-probabilities, or sample K continuations without replacement. We gather the top K
	# (as opposed to `num_beams`, or any number lower than K) so that we have at least `num_beams` sequences
	# non-finished to continue the live beam search, in case the top `num_beams` all select an EOS token.
	n_eos_tokens = eos_token_id.shape[0] if eos_token_id is not None else 0
	beams_to_keep = max(2, 1 + n_eos_tokens) * num_beams
	top_num_beam_mask = torch.cat(
	(torch.ones((num_beams), dtype=torch.bool), torch.zeros((beams_to_keep - num_beams), dtype=torch.bool)),
	dim=0,
	).to(input_ids.device)

	model_kwargs = self._get_initial_cache_position(cur_len, input_ids.device, model_kwargs)

	# (joao) feature lost in the refactor. Probably won't implement, hurts readability with minimal gains (there
	# are newer low-memory alternatives like the offloaded cache)
	sequential = generation_config.low_memory
	if sequential:
	raise ValueError(
	"`low_memory=True` is not supported after the beam search refactor. Please check the discussion in "
	"#35802 after the PR got merged, and add a comment there if your questions are not yet answered."
	)

	# 2. init output tuples
	all_scores = () if (return_dict_in_generate and output_scores) else None
	raw_logits = () if (return_dict_in_generate and output_logits) else None
	beam_indices = () if (return_dict_in_generate and output_logits) else None
	decoder_attentions = () if (return_dict_in_generate and output_attentions) else None
	cross_attentions = () if (return_dict_in_generate and output_attentions) else None
	decoder_hidden_states = () if (return_dict_in_generate and output_hidden_states) else None

	# if model is an encoder-decoder, retrieve encoder attention weights and hidden states
	if return_dict_in_generate and self.config.is_encoder_decoder:
	encoder_attentions = model_kwargs["encoder_outputs"].get("attentions") if output_attentions else None
	encoder_hidden_states = (
	model_kwargs["encoder_outputs"].get("hidden_states") if output_hidden_states else None
	)

	# 3. init running tensors and static-shaped placeholders

	# per batch, beam-item holding current token in loop and completed sequences
	output_fill_value = pad_token_id or eos_token_id[0] if eos_token_id is not None else -1
	running_sequences = torch.full(
	(batch_size, num_beams, max_length),
	fill_value=output_fill_value,
	dtype=torch.int64,
	device=input_ids.device,
	)
	running_sequences[:, :, :cur_len] = self._unflatten_beam_dim(input_ids, batch_size, num_beams)
	sequences = running_sequences.detach().clone()

	# per batch, beam-item score, logprobs
	# initialise score of first beam with 0 and the rest with -1e9. This makes sure that only tokens
	# of the first beam are considered to avoid sampling the exact same tokens across all beams.
	running_beam_scores = torch.zeros((batch_size, num_beams), dtype=torch.float, device=input_ids.device)
	running_beam_scores[:, 1:] = -1e9
	beam_scores = torch.full((batch_size, num_beams), fill_value=-1e9, dtype=torch.float, device=input_ids.device)

	# per batch, beam-item state bit indicating if sentence has finished.
	is_sent_finished = torch.zeros((batch_size, num_beams), dtype=torch.bool, device=input_ids.device)

	# per batch state bit indicating if there is a possibility to improve the best finished sentence.
	is_early_stop_heuristic_unsatisfied = torch.ones((batch_size, 1), dtype=torch.bool, device=input_ids.device)

	# per batch, beam-item state bit indicating if there are valid continuations.
	next_token_hits_stopping_criteria = torch.zeros(
	(batch_size, num_beams), dtype=torch.bool, device=input_ids.device
	)

	# per batch selected beam indices
	running_beam_indices = torch.full(
	(batch_size, num_beams, max_length - cur_len), fill_value=-1, dtype=torch.int32, device=input_ids.device
	)
	beam_indices = running_beam_indices.detach().clone()

	# 4. run the generation loop
	while self._has_unfinished_sequences(this_peer_finished, synced_gpus, device=input_ids.device):
	# a. Forward current tokens, obtain the logits
	flat_running_sequences = self._flatten_beam_dim(running_sequences[:, :, :cur_len])
	model_inputs = self.prepare_inputs_for_generation(flat_running_sequences, **model_kwargs)

	model_outputs = self(**model_inputs, return_dict=True)

	# synced_gpus: don't waste resources running the code we don't need; kwargs must be updated before skipping
	model_kwargs = self._update_model_kwargs_for_generation(
	model_outputs,
	model_kwargs,
	is_encoder_decoder=self.config.is_encoder_decoder,
	)
	if synced_gpus and this_peer_finished:
	continue

	# Copy is needed to avoid keeping a hanging ref
	logits = model_outputs.logits[:, -1, :].to(copy=True, dtype=torch.float32, device=input_ids.device)

	# b. Compute log probs -- get log probabilities from logits, process logits with processors (e.g.
	# `temperature`, ...), and add new logprobs to existing running logprobs scores.
	log_probs = nn.functional.log_softmax(logits, dim=-1)
	log_probs = logits_processor(flat_running_sequences, log_probs)

	# Store logits, attentions and hidden_states when required
	if return_dict_in_generate:
	if output_logits:
	raw_logits += (logits.clone(),)
	if return_dict_in_generate and output_scores:
	all_scores += (log_probs.clone(),)

	if output_attentions:
	decoder_attentions += (
	(model_outputs.decoder_attentions,)
	if self.config.is_encoder_decoder
	else (model_outputs.attentions,)
	)
	if self.config.is_encoder_decoder:
	cross_attentions += (model_outputs.cross_attentions,)

	if output_hidden_states:
	decoder_hidden_states += (
	(model_outputs.decoder_hidden_states,)
	if self.config.is_encoder_decoder
	else (model_outputs.hidden_states,)
	)

	# This is needed to properly delete logits which may be very large for first iteration
	# Otherwise a reference to outputs is kept which keeps the logits alive in the next iteration
	del model_outputs

	log_probs = self._unflatten_beam_dim(log_probs, batch_size, num_beams)
	log_probs = log_probs + running_beam_scores[:, :, None]
	log_probs = torch.reshape(log_probs, (batch_size, num_beams * vocab_size))

	# c. Retrieve top-K continuations, i.e. select the next token (greedy or sampling) and then keep the best
	# continuations among all beams based on the accumulated scores.
	topk_log_probs, topk_running_sequences, topk_running_beam_indices = self._get_top_k_continuations(
	accumulated_log_probs=log_probs,
	running_sequences=running_sequences,
	running_beam_indices=running_beam_indices,
	cur_len=cur_len,
	decoder_prompt_len=decoder_prompt_len,
	do_sample=do_sample,
	beams_to_keep=beams_to_keep,
	num_beams=num_beams,
	vocab_size=vocab_size,
	batch_size=batch_size,
	)

	# d. Check which running sequences have finished
	next_token_hits_stopping_criteria = stopping_criteria(
	self._flatten_beam_dim(topk_running_sequences[:, :, : cur_len + 1]), # remove unfilled token indexes
	all_scores,
	)
	next_token_hits_stopping_criteria = self._unflatten_beam_dim(
	next_token_hits_stopping_criteria, batch_size, beams_to_keep
	)

	# e. Get the non-finished running `num_beams` sequences for the next generation step
	running_sequences, running_beam_scores, running_beam_indices = self._get_running_beams_for_next_iteration(
	topk_log_probs=topk_log_probs,
	topk_running_sequences=topk_running_sequences,
	topk_running_beam_indices=topk_running_beam_indices,
	next_token_hits_stopping_criteria=next_token_hits_stopping_criteria,
	num_beams=num_beams,
	)

	# f. Update the completed beams if a new high score in a finished sequence is found
	sequences, beam_scores, beam_indices, is_sent_finished = self._update_finished_beams(
	sequences=sequences,
	topk_running_sequences=topk_running_sequences,
	beam_scores=beam_scores,
	topk_log_probs=topk_log_probs,
	beam_indices=beam_indices,
	topk_running_beam_indices=topk_running_beam_indices,
	is_early_stop_heuristic_unsatisfied=is_early_stop_heuristic_unsatisfied,
	is_sent_finished=is_sent_finished,
	next_token_hits_stopping_criteria=next_token_hits_stopping_criteria,
	top_num_beam_mask=top_num_beam_mask,
	num_beams=num_beams,
	cur_len=cur_len,
	decoder_prompt_len=decoder_prompt_len,
	length_penalty=length_penalty,
	early_stopping=early_stopping,
	)

	# g. Prepare remaining data for the next iteration, including computing the stopping condition for
	# beam search as a whole (as opposed to individual beams, i.e. `stopping_criteria`)

	# pluck the cache from the beam indices that will be used in the next iteration
	# NOTE: we need to check if `self._reorder_cache` exists for special models like RAG, RecurrentGemma etc.
	if model_kwargs.get("past_key_values", None) is not None:
	beam_idx = self._flatten_beam_dim(running_beam_indices[..., cur_len - decoder_prompt_len])
	if hasattr(self, "_reorder_cache"):
	model_kwargs["past_key_values"] = self._reorder_cache(model_kwargs["past_key_values"], beam_idx)
	else:
	model_kwargs["past_key_values"].reorder_cache(beam_idx)

	cur_len = cur_len + 1
	is_early_stop_heuristic_unsatisfied = self._check_early_stop_heuristic(
	is_early_stop_heuristic_unsatisfied=is_early_stop_heuristic_unsatisfied,
	running_beam_scores=running_beam_scores,
	beam_scores=beam_scores,
	is_sent_finished=is_sent_finished,
	cur_len=cur_len,
	max_length=max_length,
	decoder_prompt_len=decoder_prompt_len,
	early_stopping=early_stopping,
	length_penalty=length_penalty,
	)
	this_peer_finished = not self._beam_search_has_unfinished_sequences(
	is_early_stop_heuristic_unsatisfied,
	is_sent_finished,
	next_token_hits_stopping_criteria,
	early_stopping,
	)

	# 5. prepare outputs
	# Take best beams for each batch (the score is sorted in descending order)
	sequences = self._flatten_beam_dim(sequences[:, :num_return_sequences, :])
	beam_scores = self._flatten_beam_dim(beam_scores[:, :num_return_sequences])
	beam_indices = self._flatten_beam_dim(beam_indices[:, :num_return_sequences, :])

	# Crop the static-shaped tensors to the actual size.
	# `beam_indices` is initialized with -1s, and is updated with the beam index of the generated token at each
	# step. We can use it to detect the generated length, which may be != `cur_len` (e.g. selected beam is from a
	# previous decoding iteration)
	max_generated_length = ((beam_indices + 1).bool()).sum(dim=1).max()
	output_length = decoder_prompt_len + max_generated_length
	sequences = sequences[:, :output_length]
	beam_indices = beam_indices[:, :max_generated_length]

	if return_dict_in_generate:
	if not output_scores:
	beam_scores = None

	if self.config.is_encoder_decoder:
	return GenerateBeamEncoderDecoderOutput(
	sequences=sequences,
	sequences_scores=beam_scores,
	scores=all_scores,
	logits=raw_logits,
	beam_indices=beam_indices,
	encoder_attentions=encoder_attentions,
	encoder_hidden_states=encoder_hidden_states,
	decoder_attentions=decoder_attentions,
	cross_attentions=cross_attentions,
	decoder_hidden_states=decoder_hidden_states,
	past_key_values=model_kwargs.get("past_key_values"),
	)
	else:
	return GenerateBeamDecoderOnlyOutput(
	sequences=sequences,
	sequences_scores=beam_scores,
	scores=all_scores,
	logits=raw_logits,
	beam_indices=beam_indices,
	attentions=decoder_attentions,
	hidden_states=decoder_hidden_states,
	past_key_values=model_kwargs.get("past_key_values"),
	)
	else:
	return sequences

	def _assisted_decoding(
	self,
	input_ids: torch.LongTensor,
	logits_processor: LogitsProcessorList,
	stopping_criteria: StoppingCriteriaList,
	generation_config: GenerationConfig,
	synced_gpus: bool = False,
	streamer: Optional["BaseStreamer"] = None,
	inputs_tensor: Optional[torch.FloatTensor] = None,
	assistant_model: Optional["PreTrainedModel"] = None,
	assistant_tokenizer: Optional["PreTrainedTokenizerBase"] = None,
	tokenizer: Optional["PreTrainedTokenizerBase"] = None,
	**model_kwargs,
	) -> Union[GenerateNonBeamOutput, torch.LongTensor]:
	r"""
	Generates sequences of token ids for models with a language modeling head using greedy decoding or
	sample (depending on `do_sample`), assisted by candidate sequences. Assisted generation is an example of a
	candidate decoding strategy. Can be used for text-decoder, text-to-text, speech-to-text, and vision-to-text
	models.

	Parameters:
	input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`):
	The sequence used as a prompt for the generation.
	logits_processor (`LogitsProcessorList`):
	An instance of [`LogitsProcessorList`]. List of instances of class derived from [`LogitsProcessor`]
	used to modify the prediction scores of the language modeling head applied at each generation step.
	stopping_criteria (`StoppingCriteriaList`):
	An instance of [`StoppingCriteriaList`]. List of instances of class derived from [`StoppingCriteria`]
	used to tell if the generation loop should stop.
	generation_config ([`~generation.GenerationConfig`]):
	The generation configuration to be used as parametrization of the decoding method.
	synced_gpus (`bool`):
	Whether to continue running the while loop until max_length (needed to avoid deadlocking with
	`FullyShardedDataParallel` and DeepSpeed ZeRO Stage 3).
	streamer (`BaseStreamer`, optional):
	Streamer object that will be used to stream the generated sequences. Generated tokens are passed
	through `streamer.put(token_ids)` and the streamer is responsible for any further processing.
	inputs_tensor (`torch.FloatTensor`, optional):
	The input tensor for generation. For decoder models, usually `input_ids`. For encoder-decoder models,
	the tensor that produced `model_kwargs["encoder_outputs"]`.
	assistant_model (`PreTrainedModel`, optional):
	The model used to assist the generation process. If not provided, the main model will be used.
	assistant_tokenizer (`PreTrainedTokenizerBase`, optional):
	The tokenizer used for the assistant model. If not provided, the token space is assumed to be the same.
	tokenizer (`PreTrainedTokenizerBase`, optional):
	The tokenizer used for the main model. If not provided, the token space is assumed to be the same.
	model_kwargs:
	Additional model specific keyword arguments will be forwarded to the `forward` function of the model.
	If model is an encoder-decoder model the kwargs should include `encoder_outputs`.

	Return:
	[`~generation.GenerateDecoderOnlyOutput`], [`~generation.GenerateEncoderDecoderOutput`] or
	`torch.LongTensor`: A `torch.LongTensor` containing the generated tokens (default behaviour) or a
	[`~generation.GenerateDecoderOnlyOutput`] if `model.config.is_encoder_decoder=False` and
	`return_dict_in_generate=True` or a [`~generation.GenerateEncoderDecoderOutput`] if
	`model.config.is_encoder_decoder=True`.
	"""
	# The cache must be dynamic for assisted generation, and the check must happen AFTER preparing cache
	if not model_kwargs["use_cache"]:
	raise ValueError("assisted generate requires `use_cache=True`")
	if generation_config.cache_implementation in ["static", "hybrid", "sliding_window"] or (
	"past_key_values" in model_kwargs
	and hasattr(model_kwargs["past_key_values"], "layers")
	and any(getattr(l, "is_compileable", False) for l in model_kwargs["past_key_values"].layers)
	):
	raise ValueError("assisted generate is not supported with Static cache classes`")
	# Get the candidate generator, given the parameterization
	candidate_generator = self._get_candidate_generator(
	generation_config=generation_config,
	input_ids=input_ids,
	inputs_tensor=inputs_tensor,
	assistant_model=assistant_model,
	logits_processor=logits_processor,
	target_tokenizer=tokenizer,
	assistant_tokenizer=assistant_tokenizer,
	model_kwargs=model_kwargs,
	)
	# init values
	do_sample = generation_config.do_sample
	output_attentions = generation_config.output_attentions
	output_hidden_states = generation_config.output_hidden_states
	output_scores = generation_config.output_scores
	output_logits = generation_config.output_logits
	return_dict_in_generate = generation_config.return_dict_in_generate

	# init attention / hidden states / scores tuples
	scores = () if (return_dict_in_generate and output_scores) else None
	raw_logits = () if (return_dict_in_generate and output_logits) else None
	decoder_attentions = () if (return_dict_in_generate and output_attentions) else None
	cross_attentions = () if (return_dict_in_generate and output_attentions) else None
	decoder_hidden_states = () if (return_dict_in_generate and output_hidden_states) else None

	# if model is an encoder-decoder, retrieve encoder attention weights and hidden states
	if return_dict_in_generate and self.config.is_encoder_decoder:
	encoder_attentions = model_kwargs["encoder_outputs"].get("attentions") if output_attentions else None
	encoder_hidden_states = (
	model_kwargs["encoder_outputs"].get("hidden_states") if output_hidden_states else None
	)

	# keep track of which sequences are already finished
	batch_size, cur_len = input_ids.shape[:2]
	if batch_size > 1:
	raise ValueError("assisted generate is only supported for batch_size = 1")
	unfinished_sequences = torch.ones(batch_size, dtype=torch.long, device=input_ids.device)
	model_kwargs = self._get_initial_cache_position(cur_len, input_ids.device, model_kwargs)

	this_peer_finished = False
	is_first_iteration = True # to preserve the same API in the output as other generation methods
	while self._has_unfinished_sequences(this_peer_finished, synced_gpus, device=input_ids.device):
	cur_len = input_ids.shape[1]

	# 1. Fetch candidate sequences from a `CandidateGenerator` and move to the correct device
	candidate_input_ids, candidate_logits = candidate_generator.get_candidates(input_ids)
	candidate_input_ids = candidate_input_ids.to(self.device)
	if candidate_logits is not None:
	candidate_logits = candidate_logits.to(self.device)

	candidate_length = candidate_input_ids.shape[1] - input_ids.shape[1]
	is_done_candidate = stopping_criteria(candidate_input_ids, None)

	# 2. Use the original model to obtain the next token logits given the candidate sequence. We obtain
	# `candidate_length + 1` relevant logits from this process: in the event that all candidates are correct,
	# we use this forward pass to also pick the subsequent logits in the original model.

	# 2.1. Prepare the model inputs
	candidate_kwargs = copy.copy(model_kwargs)
	candidate_kwargs = _prepare_attention_mask(
	candidate_kwargs, candidate_input_ids.shape[1], self.config.is_encoder_decoder
	)
	candidate_kwargs = _prepare_token_type_ids(candidate_kwargs, candidate_input_ids.shape[1])
	if "cache_position" in candidate_kwargs:
	candidate_kwargs["cache_position"] = torch.cat(
	(
	candidate_kwargs["cache_position"],
	torch.arange(cur_len, cur_len + candidate_length, device=input_ids.device, dtype=torch.long),
	),
	dim=0,
	)

	model_inputs = self.prepare_inputs_for_generation(candidate_input_ids, **candidate_kwargs)
	if "logits_to_keep" in model_inputs:
	model_inputs["logits_to_keep"] = candidate_length + 1

	# 2.2. Run a forward pass on the candidate sequence

	outputs = self(**model_inputs)

	# 2.3. Process the new logits
	# .float() is needed to retain precision for later logits manipulations
	new_logits = outputs.logits[:, -candidate_length - 1 :].to(
	dtype=torch.float32, device=input_ids.device
	) # excludes the input prompt if present
	next_token_logits = new_logits.clone()
	if len(logits_processor) > 0:
	for i in range(candidate_length + 1):
	new_logits[:, i, :] = logits_processor(candidate_input_ids[:, : cur_len + i], new_logits[:, i, :])

	# 3. Select the accepted tokens. There are two possible cases:
	# Case 1: `do_sample=True` and we have logits for the candidates (originally from speculative decoding)
	# 👉 Apply algorithm 1 from the speculative decoding paper (https://huggingface.co/papers/2211.17192).
	if do_sample and candidate_logits is not None:
	valid_tokens, n_matches = _speculative_sampling(
	candidate_input_ids,
	candidate_logits,
	candidate_length,
	new_logits,
	is_done_candidate,
	)

	# Case 2: all other cases (originally from assisted generation) 👉 Compare the tokens selected from the
	# original model logits with the candidate tokens. We can keep the candidate tokens until the first
	# mismatch, or until the max length is reached.
	else:
	if do_sample:
	probs = new_logits.softmax(dim=-1)
	selected_tokens = torch.multinomial(probs[0, :, :], num_samples=1).squeeze(1)[None, :]
	else:
	selected_tokens = new_logits.argmax(dim=-1)

	candidate_new_tokens = candidate_input_ids[:, cur_len:]
	n_matches = ((~(candidate_new_tokens == selected_tokens[:, :-1])).cumsum(dim=-1) < 1).sum()

	# Ensure we don't generate beyond max_len or an EOS token
	if is_done_candidate and n_matches == candidate_length:
	n_matches -= 1
	valid_tokens = selected_tokens[:, : n_matches + 1]

	# 4. Update variables according to the number of matching assistant tokens. Remember: the token generated
	# by the model after the last candidate match is also valid, as it is generated from a correct sequence.
	# Because of this last token, assisted generation search reduces to a normal greedy search/sample if there
	# is no match.

	# 4.1. Get the valid continuation, after the matching tokens
	input_ids = torch.cat((input_ids, valid_tokens), dim=-1)
	if streamer is not None:
	streamer.put(valid_tokens.cpu())
	new_cur_len = input_ids.shape[1]

	# 4.2. Discard past key values relative to unused assistant tokens
	outputs.past_key_values.crop(new_cur_len - 1)

	# 5. Update the candidate generation strategy if needed
	candidate_generator.update_candidate_strategy(input_ids, new_logits, n_matches)

	# synced_gpus: don't waste resources running the code we don't need; kwargs must be updated before skipping
	model_kwargs = self._update_model_kwargs_for_generation(
	outputs,
	model_kwargs,
	is_encoder_decoder=self.config.is_encoder_decoder,
	num_new_tokens=n_matches + 1,
	)
	if synced_gpus and this_peer_finished:
	continue

	# Store scores, attentions and hidden_states when required
	# Assistant: modified to append one tuple element per token, as in the other generation methods.
	if return_dict_in_generate:
	newly_added_length = n_matches + 1
	if output_scores:
	scores += tuple(new_logits[:, i, :] for i in range(newly_added_length))
	if output_logits:
	raw_logits += tuple(next_token_logits[:, i, :] for i in range(newly_added_length))

	newly_added_length = new_cur_len if is_first_iteration else newly_added_length
	if output_attentions:
	if self.config.is_encoder_decoder:
	cross_attentions = _split_model_outputs(
	cross_attentions, outputs.cross_attentions, cur_len, newly_added_length
	)
	decoder_attentions = _split_model_outputs(
	decoder_attentions,
	outputs.decoder_attentions,
	cur_len,
	newly_added_length,
	is_decoder_attention=True,
	)
	# some (V)LLMs have hard requirement on SDPA and thus never return attn
	elif outputs.attentions[0] is not None:
	decoder_attentions = _split_model_outputs(
	decoder_attentions,
	outputs.attentions,
	cur_len,
	newly_added_length,
	is_decoder_attention=True,
	)
	if output_hidden_states:
	if self.config.is_encoder_decoder:
	decoder_hidden_states = _split_model_outputs(
	decoder_hidden_states, outputs.decoder_hidden_states, cur_len, newly_added_length
	)
	else:
	decoder_hidden_states = _split_model_outputs(
	decoder_hidden_states, outputs.hidden_states, cur_len, newly_added_length
	)

	unfinished_sequences = unfinished_sequences & ~stopping_criteria(input_ids, scores)
	this_peer_finished = unfinished_sequences.max() == 0
	is_first_iteration = False

	if streamer is not None:
	streamer.end()

	if (
	hasattr(candidate_generator, "assistant_model")
	and candidate_generator.assistant_model.generation_config.num_assistant_tokens_schedule == "heuristic"
	):
	candidate_generator.assistant_model.generation_config.num_assistant_tokens = (
	candidate_generator.num_assistant_tokens
	)
	if return_dict_in_generate:
	if self.config.is_encoder_decoder:
	return GenerateEncoderDecoderOutput(
	sequences=input_ids,
	scores=scores,
	logits=raw_logits,
	encoder_attentions=encoder_attentions,
	encoder_hidden_states=encoder_hidden_states,
	decoder_attentions=decoder_attentions,
	cross_attentions=cross_attentions,
	decoder_hidden_states=decoder_hidden_states,
	past_key_values=model_kwargs.get("past_key_values"),
	)
	else:
	return GenerateDecoderOnlyOutput(
	sequences=input_ids,
	scores=scores,
	logits=raw_logits,
	attentions=decoder_attentions,
	hidden_states=decoder_hidden_states,
	past_key_values=model_kwargs.get("past_key_values"),
	)
	else:
	return input_ids

	def _prefill_chunking(self, input_ids: torch.LongTensor, generation_config: GenerationConfig, **model_kwargs):
	# Even if we are not compiling the forward, flex is always compiled when used. With chunk prefill, we may
	# end up needing just a bit more graphs than the default (which is 8). Doing this avoids very cryptic warnings
	torch._dynamo.config.cache_size_limit = 64

	chunk_size = generation_config.prefill_chunk_size
	# Only chunk up the token just before last, so that decoding is completely performed outside this function
	# (here we simply prefill the cache)
	input_chunks = torch.split(input_ids[:, :-1], chunk_size, dim=-1)

	if "past_key_values" not in model_kwargs:
	raise ValueError("Cannot use prefill chunking without a cache")

	model_forward = self.forward

	compile_forward = self._valid_auto_compile_criteria(model_kwargs, generation_config)
	if compile_forward:
	model_forward = self.get_compiled_call(generation_config.compile_config)

	attention_mask = model_kwargs.pop("attention_mask", None)

	past_length = 0
	for input_chunk in input_chunks:
	current_length = past_length + input_chunk.shape[-1]
	# Prepare inputs
	if attention_mask is not None:
	model_kwargs["attention_mask"] = attention_mask[:, :current_length]
	model_kwargs["cache_position"] = torch.arange(
	past_length, current_length, dtype=torch.long, device=input_chunk.device
	)
	model_kwargs["position_ids"] = model_kwargs["cache_position"].unsqueeze(0)
	model_inputs = self.prepare_inputs_for_generation(input_chunk, **model_kwargs)

	outputs = model_forward(**model_inputs, return_dict=True)

	model_kwargs["past_key_values"] = outputs.past_key_values
	past_length = current_length

	model_kwargs["attention_mask"] = attention_mask
	model_kwargs["cache_position"] = model_kwargs["cache_position"][-1:] + 1
	_ = model_kwargs.pop("position_ids", None)

	return model_kwargs


	def _speculative_sampling(
	candidate_input_ids,
	candidate_logits,
	candidate_length,
	new_logits,
	is_done_candidate,
	):
	"""
	Applies sampling as in the speculative decoding paper (https://huggingface.co/papers/2211.17192, algorithm 1). Returns
	the selected tokens, as well as the number of candidate matches.

	NOTE: Unless otherwise stated, the variable names match those in the paper.
	"""
	new_candidate_input_ids = candidate_input_ids[:, -candidate_length:]
	# Gets the probabilities from the logits. q_i and p_i denote the assistant and model probabilities of the tokens
	# selected by the assistant, respectively.
	q = candidate_logits.softmax(dim=-1)
	q_i = q[:, torch.arange(candidate_length), new_candidate_input_ids].squeeze(0, 1)
	p = new_logits.softmax(dim=-1)
	p_i = p[:, torch.arange(candidate_length), new_candidate_input_ids].squeeze(0, 1)
	probability_ratio = p_i / q_i

	# When probability_ratio > 1 (i.e. q_i(x) < p_i(x), or "assistant probability of the candidate token is smaller
	# than the model probability for the same token"), keep the token. Otherwise reject with p = 1 - probability_ratio
	# (= keep with p = probability_ratio). Keep all the tokens until the first rejection
	r_i = torch.rand_like(probability_ratio)
	is_accepted = r_i <= probability_ratio
	n_matches = ((~is_accepted).cumsum(dim=-1) < 1).sum() # this is `n` in algorithm 1

	# Ensure we don't generate beyond max_len or an EOS token (not in algorithm 1, but needed for correct behavior)
	if is_done_candidate and n_matches == candidate_length:
	# Output length is assumed to be `n_matches + 1`. Since we won't generate another token with the target model
	# due to acceptance on EOS we fix `n_matches`
	n_matches -= 1
	valid_tokens = new_candidate_input_ids[:, : n_matches + 1]
	else:
	# Next token selection: if there is a rejection, adjust the distribution from the main model before sampling.
	gamma = candidate_logits.shape[1]
	p_n_plus_1 = p[:, n_matches, :]
	if n_matches < gamma:
	q_n_plus_1 = q[:, n_matches, :]
	p_prime = torch.clamp((p_n_plus_1 - q_n_plus_1), min=0)
	p_prime.div_(p_prime.sum())
	else:
	p_prime = p_n_plus_1
	t = torch.multinomial(p_prime, num_samples=1).squeeze(1)[None, :]

	# The selected tokens include the matches (if any) plus the next sampled tokens
	if n_matches > 0:
	valid_tokens = torch.cat((new_candidate_input_ids[:, :n_matches], t), dim=-1)
	else:
	valid_tokens = t

	return valid_tokens, n_matches


	def _split_model_outputs(outputs, new_outputs, cur_len, added_len, is_decoder_attention=False):
	"""
	Given the (decoder/cross attentions)/(decoder hidden states) for multiple generated tokens, splits it into a tuple
	where each member corresponds to a single generated token.
	"""
	# Retrocompatibility: in our generation functions, the first iteration includes the attention/hidden states for the
	# prompt.
	if len(outputs) == 0:
	new_tuple = ()
	for layer in new_outputs:
	last_dim_size = cur_len if is_decoder_attention else layer.shape[-1]
	new_tuple += (layer[..., :cur_len, :last_dim_size],)
	outputs += (new_tuple,)
	# The first iteration contains the prompt + 1 generated token, let's update the length variables accordingly
	cur_len += 1
	added_len -= cur_len

	for i in range(added_len):
	new_tuple = ()
	for layer in new_outputs:
	last_dim_size = cur_len + i if is_decoder_attention else layer.shape[-1]
	new_tuple += (layer[..., i : i + 1, :last_dim_size],)
	outputs += (new_tuple,)
	return outputs