This model was released on 2019-09-26 and added to Hugging Face Transformers on 2020-11-16.
ALBERT
ALBERT is designed to address memory limitations of scaling and training ofBERT. It adds two parameter reduction techniques. The first, factorized embedding parametrization, splits the larger vocabulary embedding matrix into two smaller matrices so you can grow the hidden size without adding a lot more parameters. The second, cross-layer parameter sharing, allows layer to share parameters which keeps the number of learnable parameters lower.
ALBERT was created to address problems like — GPU/TPU memory limitations, longer training times, and unexpected model degradation in BERT. ALBERT uses two parameter-reduction techniques to lower memory consumption and increase the training speed of BERT:
- Factorized embedding parameterization: The large vocabulary embedding matrix is decomposed into two smaller matrices, reducing memory consumption.
- Cross-layer parameter sharing: Instead of learning separate parameters for each transformer layer, ALBERT shares parameters across layers, further reducing the number of learnable weights.
ALBERT uses absolute position embeddings (like BERT) so padding is applied at right. Size of embeddings is 128 While BERT uses 768. ALBERT can processes maximum 512 token at a time.
You can find all the original ALBERT checkpoints under theALBERT community organization.
Click on the ALBERT models in the right sidebar for more examples of how to apply ALBERT to different language tasks.
The example below demonstrates how to predict the[MASK] token withPipeline,AutoModel, and from the command line.
import torchfrom transformersimport pipelinepipeline = pipeline( task="fill-mask", model="albert-base-v2", dtype=torch.float16, device=0)pipeline("Plants create [MASK] through a process known as photosynthesis.", top_k=5)
Notes
- Inputs should be padded on the right because BERT uses absolute position embeddings.
- The embedding size
Eis different from the hidden sizeHbecause the embeddings are context independent (one embedding vector represents one token) and the hidden states are context dependent (one hidden state represents a sequence of tokens). The embedding matrix is also larger becauseV x EwhereVis the vocabulary size. As a result, it’s more logical ifH >> E. IfE < H, the model has less parameters.
Resources
The resources provided in the following sections consist of a list of official Hugging Face and community (indicated by 🌎) resources to help you get started with AlBERT. If you’re interested in submitting a resource to be included here, please feel free to open a Pull Request and we’ll review it! The resource should ideally demonstrate something new instead of duplicating an existing resource.
AlbertForSequenceClassificationis supported by thisexample script.Check theText classification task guide on how to use the model.
AlbertForTokenClassificationis supported by thisexample script.Token classification chapter of the 🤗 Hugging Face Course.
Check theToken classification task guide on how to use the model.
AlbertForMaskedLMis supported by thisexample script andnotebook.- Masked language modeling chapter of the 🤗 Hugging Face Course.
- Check theMasked language modeling task guide on how to use the model.
AlbertForQuestionAnsweringis supported by thisexample script andnotebook.- Question answering chapter of the 🤗 Hugging Face Course.
- Check theQuestion answering task guide on how to use the model.
Multiple choice
- AlbertForMultipleChoice is supported by thisexample script andnotebook.
- Check theMultiple choice task guide on how to use the model.
AlbertConfig
classtransformers.AlbertConfig
<source>(vocab_size = 30000embedding_size = 128hidden_size = 4096num_hidden_layers = 12num_hidden_groups = 1num_attention_heads = 64intermediate_size = 16384inner_group_num = 1hidden_act = 'gelu_new'hidden_dropout_prob = 0attention_probs_dropout_prob = 0max_position_embeddings = 512type_vocab_size = 2initializer_range = 0.02layer_norm_eps = 1e-12classifier_dropout_prob = 0.1pad_token_id = 0bos_token_id = 2eos_token_id = 3**kwargs)
Parameters
- vocab_size (
int,optional, defaults to 30000) —Vocabulary size of the ALBERT model. Defines the number of different tokens that can be represented by theinputs_idspassed when callingAlbertModelorTFAlbertModel. - embedding_size (
int,optional, defaults to 128) —Dimensionality of vocabulary embeddings. - hidden_size (
int,optional, defaults to 4096) —Dimensionality of the encoder layers and the pooler layer. - num_hidden_layers (
int,optional, defaults to 12) —Number of hidden layers in the Transformer encoder. - num_hidden_groups (
int,optional, defaults to 1) —Number of groups for the hidden layers, parameters in the same group are shared. - num_attention_heads (
int,optional, defaults to 64) —Number of attention heads for each attention layer in the Transformer encoder. - intermediate_size (
int,optional, defaults to 16384) —The dimensionality of the “intermediate” (often named feed-forward) layer in the Transformer encoder. - inner_group_num (
int,optional, defaults to 1) —The number of inner repetition of attention and ffn. - hidden_act (
strorCallable,optional, defaults to"gelu_new") —The non-linear activation function (function or string) in the encoder and pooler. If string,"gelu","relu","silu"and"gelu_new"are supported. - hidden_dropout_prob (
float,optional, defaults to 0) —The dropout probability for all fully connected layers in the embeddings, encoder, and pooler. - attention_probs_dropout_prob (
float,optional, defaults to 0) —The dropout ratio for the attention probabilities. - max_position_embeddings (
int,optional, defaults to 512) —The maximum sequence length that this model might ever be used with. Typically set this to something large(e.g., 512 or 1024 or 2048). - type_vocab_size (
int,optional, defaults to 2) —The vocabulary size of thetoken_type_idspassed when callingAlbertModelorTFAlbertModel. - initializer_range (
float,optional, defaults to 0.02) —The standard deviation of the truncated_normal_initializer for initializing all weight matrices. - layer_norm_eps (
float,optional, defaults to 1e-12) —The epsilon used by the layer normalization layers. - classifier_dropout_prob (
float,optional, defaults to 0.1) —The dropout ratio for attached classifiers. - pad_token_id (
int,optional, defaults to 0) —Padding token id. - bos_token_id (
int,optional, defaults to 2) —Beginning of stream token id. - eos_token_id (
int,optional, defaults to 3) —End of stream token id.
This is the configuration class to store the configuration of aAlbertModel or aTFAlbertModel. It is usedto instantiate an ALBERT model according to the specified arguments, defining the model architecture. Instantiatinga configuration with the defaults will yield a similar configuration to that of the ALBERTalbert/albert-xxlarge-v2 architecture.
Configuration objects inherit fromPreTrainedConfig and can be used to control the model outputs. Read thedocumentation fromPreTrainedConfig for more information.
Examples:
>>>from transformersimport AlbertConfig, AlbertModel>>># Initializing an ALBERT-xxlarge style configuration>>>albert_xxlarge_configuration = AlbertConfig()>>># Initializing an ALBERT-base style configuration>>>albert_base_configuration = AlbertConfig(... hidden_size=768,... num_attention_heads=12,... intermediate_size=3072,...)>>># Initializing a model (with random weights) from the ALBERT-base style configuration>>>model = AlbertModel(albert_xxlarge_configuration)>>># Accessing the model configuration>>>configuration = model.config
AlbertTokenizer
[[autodoc]] AlbertTokenizer - build_inputs_with_special_tokens - get_special_tokens_mask - create_token_type_ids_from_sequences - save_vocabulary
AlbertTokenizerFast
classtransformers.AlbertTokenizerFast
<source>(vocab_file = Nonetokenizer_file = Nonedo_lower_case = Trueremove_space = Truekeep_accents = Falsebos_token = '[CLS]'eos_token = '[SEP]'unk_token = '<unk>'sep_token = '[SEP]'pad_token = '<pad>'cls_token = '[CLS]'mask_token = '[MASK]'**kwargs)
Parameters
- vocab_file (
str) —SentencePiece file (generally has a.spm extension) thatcontains the vocabulary necessary to instantiate a tokenizer. - do_lower_case (
bool,optional, defaults toTrue) —Whether or not to lowercase the input when tokenizing. - remove_space (
bool,optional, defaults toTrue) —Whether or not to strip the text when tokenizing (removing excess spaces before and after the string). - keep_accents (
bool,optional, defaults toFalse) —Whether or not to keep accents when tokenizing. - bos_token (
str,optional, defaults to"[CLS]") —The beginning of sequence token that was used during pretraining. Can be used a sequence classifier token.When building a sequence using special tokens, this is not the token that is used for the beginning ofsequence. The token used is the
cls_token. - eos_token (
str,optional, defaults to"[SEP]") —The end of sequence token. .. note:: When building a sequence using special tokens, this is not the tokenthat is used for the end of sequence. The token used is thesep_token. - unk_token (
str,optional, defaults to"<unk>") —The unknown token. A token that is not in the vocabulary cannot be converted to an ID and is set to be thistoken instead. - sep_token (
str,optional, defaults to"[SEP]") —The separator token, which is used when building a sequence from multiple sequences, e.g. two sequences forsequence classification or for a text and a question for question answering. It is also used as the lasttoken of a sequence built with special tokens. - pad_token (
str,optional, defaults to"<pad>") —The token used for padding, for example when batching sequences of different lengths. - cls_token (
str,optional, defaults to"[CLS]") —The classifier token which is used when doing sequence classification (classification of the whole sequenceinstead of per-token classification). It is the first token of the sequence when built with special tokens. - mask_token (
str,optional, defaults to"[MASK]") —The token used for masking values. This is the token used when training this model with masked languagemodeling. This is the token which the model will try to predict.
Construct a “fast” ALBERT tokenizer (backed by HuggingFace’stokenizers library). Based onUnigram. Thistokenizer inherits fromPreTrainedTokenizerFast which contains most of the main methods. Users should refer tothis superclass for more information regarding those methods
build_inputs_with_special_tokens
<source>(token_ids_0: listtoken_ids_1: typing.Optional[list[int]] = None)→List[int]
Parameters
- token_ids_0 (
List[int]) —List of IDs to which the special tokens will be added - token_ids_1 (
List[int],optional) —Optional second list of IDs for sequence pairs.
Returns
List[int]
list ofinput IDs with the appropriate special tokens.
Build model inputs from a sequence or a pair of sequence for sequence classification tasks by concatenating andadding special tokens. An ALBERT sequence has the following format:
- single sequence:
[CLS] X [SEP] - pair of sequences:
[CLS] A [SEP] B [SEP]
Albert specific outputs
classtransformers.models.albert.modeling_albert.AlbertForPreTrainingOutput
<source>(loss: typing.Optional[torch.FloatTensor] = Noneprediction_logits: typing.Optional[torch.FloatTensor] = Nonesop_logits: typing.Optional[torch.FloatTensor] = Nonehidden_states: typing.Optional[tuple[torch.FloatTensor]] = Noneattentions: typing.Optional[tuple[torch.FloatTensor]] = None)
Parameters
- loss (
*optional*, returned whenlabelsis provided,torch.FloatTensorof shape(1,)) —Total loss as the sum of the masked language modeling loss and the next sequence prediction(classification) loss. - prediction_logits (
torch.FloatTensorof shape(batch_size, sequence_length, config.vocab_size)) —Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax). - sop_logits (
torch.FloatTensorof shape(batch_size, 2)) —Prediction scores of the next sequence prediction (classification) head (scores of True/False continuationbefore SoftMax). - hidden_states (
tuple[torch.FloatTensor],optional, returned whenoutput_hidden_states=Trueis passed or whenconfig.output_hidden_states=True) —Tuple oftorch.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 whenoutput_attentions=Trueis passed or whenconfig.output_attentions=True) —Tuple oftorch.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-attentionheads.
Output type ofAlbertForPreTraining.
AlbertModel
[[autodoc]] AlbertModel - forward
AlbertForPreTraining
[[autodoc]] AlbertForPreTraining - forward
AlbertForMaskedLM
[[autodoc]] AlbertForMaskedLM - forward
AlbertForSequenceClassification
[[autodoc]] AlbertForSequenceClassification - forward
AlbertForMultipleChoice
classtransformers.AlbertForMultipleChoice
<source>(config: AlbertConfig)
Parameters
- config (AlbertConfig) —Model configuration class with all the parameters of the model. Initializing with a config file does notload the weights associated with the model, only the configuration. Check out thefrom_pretrained() method to load the model weights.
The Albert Model with a multiple choice classification head on top (a linear layer on top of the pooled output and asoftmax) e.g. for RocStories/SWAG tasks.
This model inherits fromPreTrainedModel. Check the superclass documentation for the generic methods thelibrary implements for all its model (such as downloading or saving, resizing the input embeddings, pruning headsetc.)
This model is also a PyTorchtorch.nn.Module subclass.Use it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usageand behavior.
forward
<source>(input_ids: typing.Optional[torch.LongTensor] = Noneattention_mask: typing.Optional[torch.FloatTensor] = Nonetoken_type_ids: typing.Optional[torch.LongTensor] = Noneposition_ids: typing.Optional[torch.LongTensor] = Noneinputs_embeds: typing.Optional[torch.FloatTensor] = Nonelabels: typing.Optional[torch.LongTensor] = None**kwargs: typing_extensions.Unpack[transformers.utils.generic.TransformersKwargs])→transformers.models.albert.modeling_albert.AlbertForPreTrainingOutput ortuple(torch.FloatTensor)
Parameters
- input_ids (
torch.LongTensorof shape(batch_size, num_choices, sequence_length)) —Indices of input sequence tokens in the vocabulary.Indices can be obtained usingAutoTokenizer. SeePreTrainedTokenizer.call() andPreTrainedTokenizer.encode() for details.
- attention_mask (
torch.FloatTensorof 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 arenot masked,
- 0 for tokens that aremasked.
- token_type_ids (
torch.LongTensorof shape(batch_size, num_choices, sequence_length),optional) —Segment token indices to indicate first and second portions of the inputs. Indices are selected in[0, 1]:- 0 corresponds to asentence A token,
- 1 corresponds to asentence B token.
- position_ids (
torch.LongTensorof shape(batch_size, num_choices, sequence_length),optional) —Indices of positions of each input sequence tokens in the position embeddings. Selected in the range[0, config.max_position_embeddings - 1]. - inputs_embeds (
torch.FloatTensorof shape(batch_size, num_choices, sequence_length, hidden_size),optional) —Optionally, instead of passinginput_idsyou can choose to directly pass an embedded representation. Thisis useful if you want more control over how to convertinput_idsindices into associated vectors than themodel’s internal embedding lookup matrix. - labels (
torch.LongTensorof shape(batch_size,),optional) —Labels for computing the multiple choice classification loss. Indices should be in[0, ..., num_choices-1]wherenum_choices is the size of the second dimension of the input tensors. (seeinput_ids above)
Returns
transformers.models.albert.modeling_albert.AlbertForPreTrainingOutput ortuple(torch.FloatTensor)
Atransformers.models.albert.modeling_albert.AlbertForPreTrainingOutput or a tuple oftorch.FloatTensor (ifreturn_dict=False is passed or whenconfig.return_dict=False) comprising variouselements depending on the configuration (AlbertConfig) and inputs.
loss (
*optional*, returned whenlabelsis provided,torch.FloatTensorof shape(1,)) — Total loss as the sum of the masked language modeling loss and the next sequence prediction(classification) loss.prediction_logits (
torch.FloatTensorof shape(batch_size, sequence_length, config.vocab_size)) — Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax).sop_logits (
torch.FloatTensorof shape(batch_size, 2)) — Prediction scores of the next sequence prediction (classification) head (scores of True/False continuationbefore SoftMax).hidden_states (
tuple[torch.FloatTensor],optional, returned whenoutput_hidden_states=Trueis passed or whenconfig.output_hidden_states=True) — Tuple oftorch.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 whenoutput_attentions=Trueis passed or whenconfig.output_attentions=True) — Tuple oftorch.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-attentionheads.
TheAlbertForMultipleChoice forward method, overrides the__call__ special method.
Although the recipe for forward pass needs to be defined within this function, one should call the
Moduleinstance afterwards instead of this since the former takes care of running the pre and post processing steps whilethe latter silently ignores them.
Example:
>>>from transformersimport AutoTokenizer, AlbertForMultipleChoice>>>import torch>>>tokenizer = AutoTokenizer.from_pretrained("albert/albert-xxlarge-v2")>>>model = AlbertForMultipleChoice.from_pretrained("albert/albert-xxlarge-v2")>>>prompt ="In Italy, pizza served in formal settings, such as at a restaurant, is presented unsliced.">>>choice0 ="It is eaten with a fork and a knife.">>>choice1 ="It is eaten while held in the hand.">>>labels = torch.tensor(0).unsqueeze(0)# choice0 is correct (according to Wikipedia ;)), batch size 1>>>encoding = tokenizer([prompt, prompt], [choice0, choice1], return_tensors="pt", padding=True)>>>outputs = model(**{k: v.unsqueeze(0)for k, vin encoding.items()}, labels=labels)# batch size is 1>>># the linear classifier still needs to be trained>>>loss = outputs.loss>>>logits = outputs.logits
AlbertForTokenClassification
[[autodoc]] AlbertForTokenClassification - forward
AlbertForQuestionAnswering
[[autodoc]] AlbertForQuestionAnswering - forward
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