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Utilities for Generation

docs/source/en/internal/generation_utils.md

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Utilities for Generation

This page lists all the utility functions used by [~generation.GenerationMixin.generate].

Generate Outputs

The output of [~generation.GenerationMixin.generate] is an instance of a subclass of [~utils.ModelOutput]. This output is a data structure containing all the information returned by [~generation.GenerationMixin.generate], but that can also be used as tuple or dictionary.

Here's an example:

python
from transformers import GPT2Tokenizer, GPT2LMHeadModel

tokenizer = GPT2Tokenizer.from_pretrained("openai-community/gpt2")
model = GPT2LMHeadModel.from_pretrained("openai-community/gpt2")

inputs = tokenizer("Hello, my dog is cute and ", return_tensors="pt")
generation_output = model.generate(**inputs, return_dict_in_generate=True, output_scores=True)

The generation_output object is a [~generation.GenerateDecoderOnlyOutput], as we can see in the documentation of that class below, it means it has the following attributes:

  • sequences: the generated sequences of tokens
  • scores (optional): the prediction scores of the language modelling head, for each generation step
  • hidden_states (optional): the hidden states of the model, for each generation step
  • attentions (optional): the attention weights of the model, for each generation step

Here we have the scores since we passed along output_scores=True, but we don't have hidden_states and attentions because we didn't pass output_hidden_states=True or output_attentions=True.

You can access each attribute as you would usually do, and if that attribute has not been returned by the model, you will get None. Here for instance generation_output.scores are all the generated prediction scores of the language modeling head, and generation_output.attentions is None.

When using our generation_output object as a tuple, it only keeps the attributes that don't have None values. Here, for instance, it has two elements, loss then logits, so

python
generation_output[:2]

will return the tuple (generation_output.sequences, generation_output.scores) for instance.

When using our generation_output object as a dictionary, it only keeps the attributes that don't have None values. Here, for instance, it has two keys that are sequences and scores.

We document here all output types.

[[autodoc]] generation.GenerateDecoderOnlyOutput

[[autodoc]] generation.GenerateEncoderDecoderOutput

[[autodoc]] generation.GenerateBeamDecoderOnlyOutput

[[autodoc]] generation.GenerateBeamEncoderDecoderOutput

LogitsProcessor

A [LogitsProcessor] can be used to modify the prediction scores of a language model head for generation.

[[autodoc]] AlternatingCodebooksLogitsProcessor - call

[[autodoc]] ClassifierFreeGuidanceLogitsProcessor - call

[[autodoc]] EncoderNoRepeatNGramLogitsProcessor - call

[[autodoc]] EncoderRepetitionPenaltyLogitsProcessor - call

[[autodoc]] EpsilonLogitsWarper - call

[[autodoc]] EtaLogitsWarper - call

[[autodoc]] ExponentialDecayLengthPenalty - call

[[autodoc]] ForcedBOSTokenLogitsProcessor - call

[[autodoc]] ForcedEOSTokenLogitsProcessor - call

[[autodoc]] InfNanRemoveLogitsProcessor - call

[[autodoc]] LogitNormalization - call

[[autodoc]] LogitsProcessor - call

[[autodoc]] LogitsProcessorList - call

[[autodoc]] MinLengthLogitsProcessor - call

[[autodoc]] MinNewTokensLengthLogitsProcessor - call

[[autodoc]] MinPLogitsWarper - call

[[autodoc]] NoBadWordsLogitsProcessor - call

[[autodoc]] NoRepeatNGramLogitsProcessor - call

[[autodoc]] PrefixConstrainedLogitsProcessor - call

[[autodoc]] RepetitionPenaltyLogitsProcessor - call

[[autodoc]] SequenceBiasLogitsProcessor - call

[[autodoc]] SuppressTokensAtBeginLogitsProcessor - call

[[autodoc]] SuppressTokensLogitsProcessor - call

[[autodoc]] SynthIDTextWatermarkLogitsProcessor - call

[[autodoc]] TemperatureLogitsWarper - call

[[autodoc]] TopHLogitsWarper - call

[[autodoc]] TopKLogitsWarper - call

[[autodoc]] TopPLogitsWarper - call

[[autodoc]] TypicalLogitsWarper - call

[[autodoc]] UnbatchedClassifierFreeGuidanceLogitsProcessor - call

[[autodoc]] WhisperTimeStampLogitsProcessor - call

[[autodoc]] WatermarkLogitsProcessor - call

StoppingCriteria

A [StoppingCriteria] can be used to change when to stop generation (other than EOS token). Please note that this is exclusively available to our PyTorch implementations.

[[autodoc]] StoppingCriteria - call

[[autodoc]] StoppingCriteriaList - call

[[autodoc]] MaxLengthCriteria - call

[[autodoc]] MaxTimeCriteria - call

[[autodoc]] StopStringCriteria - call

[[autodoc]] EosTokenCriteria - call

Streamers

[[autodoc]] TextStreamer

[[autodoc]] TextIteratorStreamer

[[autodoc]] AsyncTextIteratorStreamer

Caches

[[autodoc]] CacheLayerMixin - update - get_seq_length - get_mask_sizes - get_max_cache_shape - reset - reorder_cache - lazy_initialization

[[autodoc]] DynamicLayer - update - lazy_initialization - crop - batch_repeat_interleave - batch_select_indices

[[autodoc]] StaticLayer - update - lazy_initialization

[[autodoc]] StaticSlidingWindowLayer - update - lazy_initialization

[[autodoc]] QuantoQuantizedLayer - update - lazy_initialization

[[autodoc]] HQQQuantizedLayer - update - lazy_initialization

[[autodoc]] Cache - update - early_initialization - get_seq_length - get_mask_sizes - get_max_cache_shape - reset - reorder_cache - crop - batch_repeat_interleave - batch_select_indices

[[autodoc]] DynamicCache

[[autodoc]] StaticCache

[[autodoc]] QuantizedCache

[[autodoc]] EncoderDecoderCache

Watermark Utils

[[autodoc]] WatermarkingConfig - call

[[autodoc]] WatermarkDetector - call

[[autodoc]] BayesianDetectorConfig

[[autodoc]] BayesianDetectorModel - forward

[[autodoc]] SynthIDTextWatermarkingConfig

[[autodoc]] SynthIDTextWatermarkDetector - call

Compile Utils

[[autodoc]] CompileConfig - call