Hugging Face's logo

Transformers documentation

ModernBERT Decoder

You are viewing main version, which requires installation from source. If you'd like regular pip install, checkout the latest stable version (v4.53.2).
Hugging Face's logo
Join the Hugging Face community

and get access to the augmented documentation experience

to get started

PyTorch FlashAttention SDPA

ModernBERT Decoder

ModernBERT Decoder is the same architecture as ModernBERT but trained from scratch with a causal language modeling (CLM) objective. This allows for using the same architecture for comparing encoders and decoders. This is the decoder architecture implementation of ModernBERT, designed for autoregressive text generation tasks.

Like the encoder version, ModernBERT Decoder incorporates modern architectural improvements such as rotary positional embeddings to support sequences of up to 8192 tokens, unpadding to avoid wasting compute on padding tokens, GeGLU layers, and alternating attention patterns. However, it uses causal (unidirectional) attention to enable autoregressive generation.

Click on the ModernBERT Decoder models in the right sidebar for more examples of how to apply ModernBERT Decoder to different text generation tasks.

The example below demonstrates how to use ModernBERT Decoder for text generation with Pipeline, AutoModel, and from the command line.

Pipeline
AutoModel
transformers CLI 
import torch
from transformers import pipeline

generator = pipeline(
    task="text-generation",
    model="blab-jhu/test-32m-dec",
    torch_dtype=torch.float16,
    device=0
)
generator("The future of artificial intelligence is", max_length=50, num_return_sequences=1)

# For sequence classification
classifier = pipeline(
    task="text-classification",
    model="blab-jhu/test-32m-dec",
    torch_dtype=torch.float16,
    device=0
)
classifier("This movie is really great!")

ModernBertDecoderConfig

class transformers.ModernBertDecoderConfig

< >

( vocab_size = 50368 hidden_size = 768 intermediate_size = 1152 num_hidden_layers = 22 num_attention_heads = 12 hidden_activation = 'gelu' max_position_embeddings = 8192 initializer_range = 0.02 initializer_cutoff_factor = 2.0 norm_eps = 1e-05 norm_bias = False pad_token_id = 50283 eos_token_id = 50282 bos_token_id = 50281 cls_token_id = 50281 sep_token_id = 50282 global_rope_theta = 160000.0 attention_bias = False attention_dropout = 0.0 embedding_dropout = 0.0 mlp_bias = False mlp_dropout = 0.0 decoder_bias = True classifier_dropout = 0.0 classifier_bias = False classifier_activation = 'gelu' use_cache = True local_attention = 128 global_attn_every_n_layers = 3 local_rope_theta = 160000.0 layer_types = None **kwargs )

Parameters

  • vocab_size (int, optional, defaults to 50368) — Vocabulary size of the ModernBert decoder model. Defines the number of different tokens that can be represented by the inputs_ids passed when calling ModernBertDecoderModel
  • hidden_size (int, optional, defaults to 768) — Dimension of the hidden representations.
  • intermediate_size (int, optional, defaults to 1152) — Dimension of the MLP representations.
  • num_hidden_layers (int, optional, defaults to 22) — Number of hidden layers in the Transformer decoder.
  • num_attention_heads (int, optional, defaults to 12) — Number of attention heads for each attention layer in the Transformer decoder.
  • hidden_activation (str or function, optional, defaults to "gelu") — The non-linear activation function (function or string) in the decoder. Will default to "gelu" if not specified.
  • max_position_embeddings (int, optional, defaults to 8192) — The maximum sequence length that this model might ever be used with.
  • initializer_range (float, optional, defaults to 0.02) — The standard deviation of the truncated_normal_initializer for initializing all weight matrices.
  • initializer_cutoff_factor (float, optional, defaults to 2.0) — The cutoff factor for the truncated_normal_initializer for initializing all weight matrices.
  • norm_eps (float, optional, defaults to 1e-05) — The epsilon used by the rms normalization layers.
  • norm_bias (bool, optional, defaults to False) — Whether to use bias in the normalization layers.
  • pad_token_id (int, optional, defaults to 50283) — Padding token id.
  • eos_token_id (int, optional, defaults to 50282) — End of stream token id.
  • bos_token_id (int, optional, defaults to 50281) — Beginning of stream token id.
  • cls_token_id (int, optional, defaults to 50281) — Classification token id.
  • sep_token_id (int, optional, defaults to 50282) — Separation token id.
  • global_rope_theta (float, optional, defaults to 160000.0) — The base period of the global RoPE embeddings.
  • attention_bias (bool, optional, defaults to False) — Whether to use a bias in the query, key, value and output projection layers during self-attention.
  • attention_dropout (float, optional, defaults to 0.0) — The dropout ratio for the attention probabilities.
  • embedding_dropout (float, optional, defaults to 0.0) — The dropout ratio for the embeddings.
  • mlp_bias (bool, optional, defaults to False) — Whether to use bias in the MLP layers.
  • mlp_dropout (float, optional, defaults to 0.0) — The dropout ratio for the MLP layers.
  • decoder_bias (bool, optional, defaults to True) — Whether to use bias in the decoder layers.
  • classifier_dropout (float, optional, defaults to 0.0) — The dropout ratio for the classifier.
  • classifier_bias (bool, optional, defaults to False) — Whether to use bias in the classifier.
  • classifier_activation (str, optional, defaults to "gelu") — The activation function for the classifier.
  • use_cache (bool, optional, defaults to True) — Whether or not the model should return the last key/values attentions (not used by all models). Only relevant if config.is_decoder=True.
  • local_attention (int, optional, defaults to 128) — The sliding window size for local attention. Only used for layers that use local attention. Note that for the decoder to match ModernBERT this is actually half of the sliding window size, so 128 => 64.
  • global_attn_every_n_layers (int, optional, defaults to 3) — Every global_attn_every_n_layers layers will use global attention instead of local attention.
  • local_rope_theta (float, optional, defaults to 160000.0) — The base period of the local RoPE embeddings. If not specified, defaults to 160000.0
  • layer_types (list, optional) — List of layer types, one for each layer. If not specified, will be automatically generated based on global_attn_every_n_layers. Should contain “full_attention” or “sliding_attention”.

This is the configuration class to store the configuration of a ModernBertDecoderModel. It is used to instantiate a ModernBert decoder model according to the specified arguments, defining the model architecture. Instantiating a configuration with the defaults will yield a similar configuration to that of the ModernBERT-base decoder. e.g. blab-jhu/test-32m-dec

Configuration objects inherit from PretrainedConfig and can be used to control the model outputs. Read the documentation from PretrainedConfig for more information.

Examples:

>>> from transformers import ModernBertDecoderModel, ModernBertDecoderConfig

>>> # Initializing a ModernBert decoder style configuration
>>> configuration = ModernBertDecoderConfig()

>>> # Initializing a model from the modernbert-base decoder style configuration
>>> model = ModernBertDecoderModel(configuration)

>>> # Accessing the model configuration
>>> configuration = model.config
Pytorch
Hide Pytorch content

ModernBertDecoderModel

class transformers.ModernBertDecoderModel

< >

( config: ModernBertDecoderConfig )

Parameters

  • config (ModernBertDecoderConfig) — Model configuration class with all the parameters of the model. Initializing with a config file does not load the weights associated with the model, only the configuration. Check out the from_pretrained() method to load the model weights.

The bare Modernbert Decoder Model outputting raw hidden-states without any specific head on top.

This model inherits from PreTrainedModel. Check the superclass documentation for the generic methods the library implements for all its model (such as downloading or saving, resizing the input embeddings, pruning heads etc.)

This model is also a PyTorch torch.nn.Module subclass. Use it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage and behavior.

forward

< >

( input_ids: typing.Optional[torch.LongTensor] = None attention_mask: typing.Optional[torch.Tensor] = None position_ids: typing.Optional[torch.LongTensor] = None past_key_values: typing.Optional[transformers.cache_utils.Cache] = None inputs_embeds: typing.Optional[torch.Tensor] = None use_cache: typing.Optional[bool] = None cache_position: typing.Optional[torch.LongTensor] = None **kwargs ) → transformers.modeling_outputs.BaseModelOutputWithPast or tuple(torch.FloatTensor)

Parameters

  • input_ids (torch.LongTensor of shape (batch_size, sequence_length), optional) — Indices of input sequence tokens in the vocabulary. Padding will be ignored by default.

    Indices can be obtained using AutoTokenizer. See PreTrainedTokenizer.encode() and PreTrainedTokenizer.call() for details.

    What are input IDs?

  • attention_mask (torch.Tensor of shape (batch_size, sequence_length), optional) — Mask to avoid performing attention on padding token indices. Mask values selected in [0, 1]:

    • 1 for tokens that are not masked,
    • 0 for tokens that are masked.

    What are attention masks?

  • position_ids (torch.LongTensor of shape (batch_size, sequence_length), optional) — Indices of positions of each input sequence tokens in the position embeddings. Selected in the range [0, config.n_positions - 1].

    What are position IDs?

  • past_key_values (~cache_utils.Cache, optional) — Pre-computed hidden-states (key and values in the self-attention blocks and in the cross-attention blocks) that can be used to speed up sequential decoding. This typically consists in the past_key_values returned by the model at a previous stage of decoding, when use_cache=True or config.use_cache=True.

    Only Cache instance is allowed as input, see our kv cache guide. If no past_key_values are passed, DynamicCache will be initialized by default.

    The model will output the same cache format that is fed as input.

    If past_key_values are used, the user is expected to input only unprocessed input_ids (those that don’t have their past key value states given to this model) of shape (batch_size, unprocessed_length) instead of all input_ids of shape (batch_size, sequence_length).

  • inputs_embeds (torch.Tensor of shape (batch_size, sequence_length, hidden_size), optional) — Optionally, instead of passing input_ids you can choose to directly pass an embedded representation. This is useful if you want more control over how to convert input_ids indices into associated vectors than the model’s internal embedding lookup matrix.
  • use_cache (bool, optional) — If set to True, past_key_values key value states are returned and can be used to speed up decoding (see past_key_values).
  • cache_position (torch.LongTensor of shape (sequence_length), optional) — Indices depicting the position of the input sequence tokens in the sequence. Contrarily to position_ids, this tensor is not affected by padding. It is used to update the cache in the correct position and to infer the complete sequence length.

Returns

transformers.modeling_outputs.BaseModelOutputWithPast or tuple(torch.FloatTensor)

A transformers.modeling_outputs.BaseModelOutputWithPast or a tuple of torch.FloatTensor (if return_dict=False is passed or when config.return_dict=False) comprising various elements depending on the configuration (ModernBertDecoderConfig) and inputs.

  • last_hidden_state (torch.FloatTensor of shape (batch_size, sequence_length, hidden_size)) — Sequence of hidden-states at the output of the last layer of the model.

    If past_key_values is used only the last hidden-state of the sequences of shape (batch_size, 1, hidden_size) is output.

  • past_key_values (Cache, optional, returned when use_cache=True is passed or when config.use_cache=True) — It is a Cache instance. For more details, see our kv cache guide.

    Contains pre-computed hidden-states (key and values in the self-attention blocks and optionally if config.is_encoder_decoder=True in the cross-attention blocks) that can be used (see past_key_values input) to speed up sequential decoding.

  • hidden_states (tuple(torch.FloatTensor), optional, returned when output_hidden_states=True is passed or when config.output_hidden_states=True) — Tuple of torch.FloatTensor (one for the output of the embeddings, if the model has an embedding layer, + one for the output of each layer) of shape (batch_size, sequence_length, hidden_size).

    Hidden-states of the model at the output of each layer plus the optional initial embedding outputs.

  • attentions (tuple(torch.FloatTensor), optional, returned when output_attentions=True is passed or when config.output_attentions=True) — Tuple of torch.FloatTensor (one for each layer) of shape (batch_size, num_heads, sequence_length, sequence_length).

    Attentions weights after the attention softmax, used to compute the weighted average in the self-attention heads.

The ModernBertDecoderModel forward method, overrides the __call__ special method.

Although the recipe for forward pass needs to be defined within this function, one should call the Module instance afterwards instead of this since the former takes care of running the pre and post processing steps while the latter silently ignores them.

ModernBertDecoderForCausalLM

class transformers.ModernBertDecoderForCausalLM

< >

( config: ModernBertDecoderConfig )

Parameters

  • config (ModernBertDecoderConfig) — Model configuration class with all the parameters of the model. Initializing with a config file does not load the weights associated with the model, only the configuration. Check out the from_pretrained() method to load the model weights.

The ModernBert Decoder Model with a language modeling head on top for causal language modeling (CLM).

This model inherits from PreTrainedModel. Check the superclass documentation for the generic methods the library implements for all its model (such as downloading or saving, resizing the input embeddings, pruning heads etc.)

This model is also a PyTorch torch.nn.Module subclass. Use it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage and behavior.

forward

< >

( input_ids: typing.Optional[torch.LongTensor] = None attention_mask: typing.Optional[torch.Tensor] = None position_ids: typing.Optional[torch.LongTensor] = None past_key_values: typing.Optional[transformers.cache_utils.Cache] = None inputs_embeds: typing.Optional[torch.Tensor] = None labels: typing.Optional[torch.LongTensor] = None use_cache: typing.Optional[bool] = None **kwargs )

Parameters

  • input_ids (torch.LongTensor of shape (batch_size, sequence_length), optional) — Indices of input sequence tokens in the vocabulary. Padding will be ignored by default.

    Indices can be obtained using AutoTokenizer. See PreTrainedTokenizer.encode() and PreTrainedTokenizer.call() for details.

    What are input IDs?

  • attention_mask (torch.Tensor of shape (batch_size, sequence_length), optional) — Mask to avoid performing attention on padding token indices. Mask values selected in [0, 1]:

    • 1 for tokens that are not masked,
    • 0 for tokens that are masked.

    What are attention masks?

  • position_ids (torch.LongTensor of shape (batch_size, sequence_length), optional) — Indices of positions of each input sequence tokens in the position embeddings. Selected in the range [0, config.n_positions - 1].

    What are position IDs?

  • past_key_values (~cache_utils.Cache, optional) — Pre-computed hidden-states (key and values in the self-attention blocks and in the cross-attention blocks) that can be used to speed up sequential decoding. This typically consists in the past_key_values returned by the model at a previous stage of decoding, when use_cache=True or config.use_cache=True.

    Only Cache instance is allowed as input, see our kv cache guide. If no past_key_values are passed, DynamicCache will be initialized by default.

    The model will output the same cache format that is fed as input.

    If past_key_values are used, the user is expected to input only unprocessed input_ids (those that don’t have their past key value states given to this model) of shape (batch_size, unprocessed_length) instead of all input_ids of shape (batch_size, sequence_length).

  • inputs_embeds (torch.Tensor of shape (batch_size, sequence_length, hidden_size), optional) — Optionally, instead of passing input_ids you can choose to directly pass an embedded representation. This is useful if you want more control over how to convert input_ids indices into associated vectors than the model’s internal embedding lookup matrix.
  • labels (torch.LongTensor of shape (batch_size, sequence_length), optional) — Labels for computing the masked language modeling loss. Indices should either be in [0, ..., config.vocab_size] or -100 (see input_ids docstring). Tokens with indices set to -100 are ignored (masked), the loss is only computed for the tokens with labels in [0, ..., config.vocab_size].
  • use_cache (bool, optional) — If set to True, past_key_values key value states are returned and can be used to speed up decoding (see past_key_values).

The ModernBertDecoderForCausalLM forward method, overrides the __call__ special method.

Although the recipe for forward pass needs to be defined within this function, one should call the Module instance afterwards instead of this since the former takes care of running the pre and post processing steps while the latter silently ignores them.

Example:

>>> from transformers import AutoTokenizer, ModernBertDecoderForCausalLM

>>> model = ModernBertDecoderForCausalLM.from_pretrained("blab-jhu/test-32m-dec")
>>> tokenizer = AutoTokenizer.from_pretrained("blab-jhu/test-32m-dec")

>>> prompt = "The capital of France is"
>>> inputs = tokenizer(prompt, return_tensors="pt")

>>> # Generate
>>> generate_ids = model.generate(inputs.input_ids, max_length=1)
>>> tokenizer.batch_decode(generate_ids, skip_special_tokens=True, clean_up_tokenization_spaces=False)[0]
"The capital of France is Paris"

ModernBertDecoderForSequenceClassification

class transformers.ModernBertDecoderForSequenceClassification

< >

( config: ModernBertDecoderConfig )

Parameters

  • config (ModernBertDecoderConfig) — Model configuration class with all the parameters of the model. Initializing with a config file does not load the weights associated with the model, only the configuration. Check out the from_pretrained() method to load the model weights.

The ModernBert Decoder Model with a sequence classification head on top (linear layer).

ModernBertDecoderForSequenceClassification uses the last token in order to do the classification, as other causal models (e.g. GPT-1, GPT-2) do.

Since it does classification on the last token, it requires to know the position of the last token. If a pad_token_id is defined in the configuration, it finds the last token that is not a padding token in each row. If no pad_token_id is defined, it simply takes the last value in each row of the batch. Since it cannot guess the padding tokens when inputs_embeds are passed instead of input_ids, it does the same (take the last value in each row of the batch).

This model inherits from PreTrainedModel. Check the superclass documentation for the generic methods the library implements for all its model (such as downloading or saving, resizing the input embeddings, pruning heads etc.)

This model is also a PyTorch torch.nn.Module subclass. Use it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage and behavior.

forward

< >

( input_ids: typing.Optional[torch.LongTensor] = None attention_mask: typing.Optional[torch.Tensor] = None position_ids: typing.Optional[torch.LongTensor] = None past_key_values: typing.Optional[transformers.cache_utils.Cache] = None inputs_embeds: typing.Optional[torch.Tensor] = None labels: typing.Optional[torch.LongTensor] = None use_cache: typing.Optional[bool] = None **kwargs ) → transformers.modeling_outputs.SequenceClassifierOutputWithPast or tuple(torch.FloatTensor)

Parameters

  • input_ids (torch.LongTensor of shape (batch_size, sequence_length), optional) — Indices of input sequence tokens in the vocabulary. Padding will be ignored by default.

    Indices can be obtained using AutoTokenizer. See PreTrainedTokenizer.encode() and PreTrainedTokenizer.call() for details.

    What are input IDs?

  • attention_mask (torch.Tensor of shape (batch_size, sequence_length), optional) — Mask to avoid performing attention on padding token indices. Mask values selected in [0, 1]:

    • 1 for tokens that are not masked,
    • 0 for tokens that are masked.

    What are attention masks?

  • position_ids (torch.LongTensor of shape (batch_size, sequence_length), optional) — Indices of positions of each input sequence tokens in the position embeddings. Selected in the range [0, config.n_positions - 1].

    What are position IDs?

  • past_key_values (~cache_utils.Cache, optional) — Pre-computed hidden-states (key and values in the self-attention blocks and in the cross-attention blocks) that can be used to speed up sequential decoding. This typically consists in the past_key_values returned by the model at a previous stage of decoding, when use_cache=True or config.use_cache=True.

    Only Cache instance is allowed as input, see our kv cache guide. If no past_key_values are passed, DynamicCache will be initialized by default.

    The model will output the same cache format that is fed as input.

    If past_key_values are used, the user is expected to input only unprocessed input_ids (those that don’t have their past key value states given to this model) of shape (batch_size, unprocessed_length) instead of all input_ids of shape (batch_size, sequence_length).

  • inputs_embeds (torch.Tensor of shape (batch_size, sequence_length, hidden_size), optional) — Optionally, instead of passing input_ids you can choose to directly pass an embedded representation. This is useful if you want more control over how to convert input_ids indices into associated vectors than the model’s internal embedding lookup matrix.
  • labels (torch.LongTensor of shape (batch_size,), optional) — Labels for computing the sequence classification/regression loss. Indices should be in [0, ..., config.num_labels - 1]. If config.num_labels == 1 a regression loss is computed (Mean-Square loss), If config.num_labels > 1 a classification loss is computed (Cross-Entropy).
  • use_cache (bool, optional) — If set to True, past_key_values key value states are returned and can be used to speed up decoding (see past_key_values).

Returns

transformers.modeling_outputs.SequenceClassifierOutputWithPast or tuple(torch.FloatTensor)

A transformers.modeling_outputs.SequenceClassifierOutputWithPast or a tuple of torch.FloatTensor (if return_dict=False is passed or when config.return_dict=False) comprising various elements depending on the configuration (ModernBertDecoderConfig) and inputs.

  • loss (torch.FloatTensor of shape (1,), optional, returned when labels is provided) — Classification (or regression if config.num_labels==1) loss.

  • logits (torch.FloatTensor of shape (batch_size, config.num_labels)) — Classification (or regression if config.num_labels==1) scores (before SoftMax).

  • past_key_values (Cache, optional, returned when use_cache=True is passed or when config.use_cache=True) — It is a Cache instance. For more details, see our kv cache guide.

    Contains pre-computed hidden-states (key and values in the self-attention blocks) that can be used (see past_key_values input) to speed up sequential decoding.

  • hidden_states (tuple(torch.FloatTensor), optional, returned when output_hidden_states=True is passed or when config.output_hidden_states=True) — Tuple of torch.FloatTensor (one for the output of the embeddings, if the model has an embedding layer, + one for the output of each layer) of shape (batch_size, sequence_length, hidden_size).

    Hidden-states of the model at the output of each layer plus the optional initial embedding outputs.

  • attentions (tuple(torch.FloatTensor), optional, returned when output_attentions=True is passed or when config.output_attentions=True) — Tuple of torch.FloatTensor (one for each layer) of shape (batch_size, num_heads, sequence_length, sequence_length).

    Attentions weights after the attention softmax, used to compute the weighted average in the self-attention heads.

The ModernBertDecoderForSequenceClassification forward method, overrides the __call__ special method.

Although the recipe for forward pass needs to be defined within this function, one should call the Module instance afterwards instead of this since the former takes care of running the pre and post processing steps while the latter silently ignores them.

Example of single-label classification:

>>> import torch
>>> from transformers import AutoTokenizer, ModernBertDecoderForSequenceClassification

>>> tokenizer = AutoTokenizer.from_pretrained("blab-jhu/test-32m-dec")
>>> model = ModernBertDecoderForSequenceClassification.from_pretrained("blab-jhu/test-32m-dec")

>>> inputs = tokenizer("Hello, my dog is cute", return_tensors="pt")

>>> with torch.no_grad():
...     logits = model(**inputs).logits

>>> predicted_class_id = logits.argmax().item()
>>> model.config.id2label[predicted_class_id]
...

>>> # To train a model on `num_labels` classes, you can pass `num_labels=num_labels` to `.from_pretrained(...)`
>>> num_labels = len(model.config.id2label)
>>> model = ModernBertDecoderForSequenceClassification.from_pretrained("blab-jhu/test-32m-dec", num_labels=num_labels)

>>> labels = torch.tensor([1])
>>> loss = model(**inputs, labels=labels).loss
>>> round(loss.item(), 2)
...

Example of multi-label classification:

>>> import torch
>>> from transformers import AutoTokenizer, ModernBertDecoderForSequenceClassification

>>> tokenizer = AutoTokenizer.from_pretrained("blab-jhu/test-32m-dec")
>>> model = ModernBertDecoderForSequenceClassification.from_pretrained("blab-jhu/test-32m-dec", problem_type="multi_label_classification")

>>> inputs = tokenizer("Hello, my dog is cute", return_tensors="pt")

>>> with torch.no_grad():
...     logits = model(**inputs).logits

>>> predicted_class_ids = torch.arange(0, logits.shape[-1])[torch.sigmoid(logits).squeeze(dim=0) > 0.5]

>>> # To train a model on `num_labels` classes, you can pass `num_labels=num_labels` to `.from_pretrained(...)`
>>> num_labels = len(model.config.id2label)
>>> model = ModernBertDecoderForSequenceClassification.from_pretrained(
...     "blab-jhu/test-32m-dec", num_labels=num_labels, problem_type="multi_label_classification"
... )

>>> labels = torch.sum(
...     torch.nn.functional.one_hot(predicted_class_ids[None, :].clone(), num_classes=num_labels), dim=1
... ).to(torch.float)
>>> loss = model(**inputs, labels=labels).loss

Usage tips

The ModernBertDecoder model can be fine-tuned for various text generation tasks using the HuggingFace Transformers library. It supports efficient inference with features like:

  • Causal attention: Ensures autoregressive generation by masking future tokens
  • Sliding window attention: Alternates between local and global attention patterns for efficiency
  • Rotary positional embeddings: Enables handling of longer sequences up to 8000 tokens
  • FlashAttention support: Optimized attention computation for faster training and inference
< > Update on GitHub

←ModernBert MPNet→