CuratedTransformer
This pipeline component lets you use a curated set of transformer models in your pipeline. spaCy Curated Transformers currently supports the following model types:
- ALBERT
- BERT
- CamemBERT
- RoBERTa
- XLM-RoBERT
If you want to use another type of model, use spacy-transformers, which allows you to use all Hugging Face transformer models with spaCy.
You will usually connect downstream components to a shared Curated Transformer
pipe using one of the Curated Transformer listener layers. This works similarly
to spaCy’s Tok2Vec, and the
Tok2VecListener sublayer. The component
assigns the output of the transformer to the Doc
’s extension attributes. To
access the values, you can use the custom
Doc._.trf_data
attribute.
For more details, see the usage documentation.
Assigned Attributes
The component sets the following custom extension attribute:
Location | Value |
---|---|
Doc._.trf_data | Curated Transformer outputs for the Doc object. DocTransformerOutput |
Config and Implementation
The default config is defined by the pipeline component factory and describes
how the component should be configured. You can override its settings via the
config
argument on nlp.add_pipe
or in your
config.cfg
for training. See the
model architectures documentation for details
on the curated transformer architectures and their arguments and
hyperparameters.
Setting | Description |
---|---|
model | The Thinc Model wrapping the transformer. Defaults to XlmrTransformer . Model |
frozen | If True , the model’s weights are frozen and no backpropagation is performed. bool |
all_layer_outputs | If True , the model returns the outputs of all the layers. Otherwise, only the output of the last layer is returned. This must be set to True if any of the pipe’s downstream listeners require the outputs of all transformer layers. bool |
explosion/spacy-curated-transformers/main/spacy_curated_transformers/pipeline/transformer.py
CuratedTransformer.__init__ method
Construct a CuratedTransformer
component. One or more subsequent spaCy
components can use the transformer outputs as features in its model, with
gradients backpropagated to the single shared weights. The activations from the
transformer are saved in the Doc._.trf_data
extension
attribute. You can also provide a callback to set additional annotations. In
your application, you would normally use a shortcut for this and instantiate the
component using its string name and nlp.add_pipe
.
Name | Description |
---|---|
vocab | The shared vocabulary. Vocab |
model | One of the supported pre-trained transformer models. Model |
keyword-only | |
name | The component instance name. str |
frozen | If True , the model’s weights are frozen and no backpropagation is performed. bool |
all_layer_outputs | If True , the model returns the outputs of all the layers. Otherwise, only the output of the last layer is returned. This must be set to True if any of the pipe’s downstream listeners require the outputs of all transformer layers. bool |
CuratedTransformer.__call__ method
Apply the pipe to one document. The document is modified in place, and returned.
This usually happens under the hood when the nlp
object is called on a text
and all pipeline components are applied to the Doc
in order. Both
__call__
and
pipe
delegate to the
predict
and
set_annotations
methods.
Name | Description |
---|---|
doc | The document to process. Doc |
RETURNS | The processed document. Doc |
CuratedTransformer.pipe method
Apply the pipe to a stream of documents. This usually happens under the hood
when the nlp
object is called on a text and all pipeline components are
applied to the Doc
in order. Both __call__
and pipe
delegate to the
predict
and
set_annotations
methods.
Name | Description |
---|---|
stream | A stream of documents. Iterable[Doc] |
keyword-only | |
batch_size | The number of documents to buffer. Defaults to 128 . int |
YIELDS | The processed documents in order. Doc |
CuratedTransformer.initialize method
Initialize the component for training and return an
Optimizer
. get_examples
should be a
function that returns an iterable of Example
objects. At
least one example should be supplied. The data examples are used to
initialize the model of the component and can either be the full training
data or a representative sample. Initialization includes validating the network,
inferring missing shapes and
setting up the label scheme based on the data. This method is typically called
by Language.initialize
.
Name | Description |
---|---|
get_examples | Function that returns gold-standard annotations in the form of Example objects. Must contain at least one Example . Callable[[], Iterable[Example]] |
keyword-only | |
nlp | The current nlp object. Defaults to None . Optional[Language] |
encoder_loader | Initialization callback for the transformer model. Optional[Callable] |
piece_loader | Initialization callback for the input piece encoder. Optional[Callable] |
CuratedTransformer.predict method
Apply the component’s model to a batch of Doc
objects without
modifying them.
Name | Description |
---|---|
docs | The documents to predict. Iterable[Doc] |
RETURNS | The model’s prediction for each document. |
CuratedTransformer.set_annotations method
Assign the extracted features to the Doc
objects. By default, the
DocTransformerOutput
object is
written to the Doc._.trf_data
attribute. Your
set_extra_annotations
callback is then called, if provided.
Name | Description |
---|---|
docs | The documents to modify. Iterable[Doc] |
scores | The scores to set, produced by CuratedTransformer.predict . |
CuratedTransformer.update method
Prepare for an update to the transformer.
Like the Tok2Vec
component, the CuratedTransformer
component
is unusual in that it does not receive “gold standard” annotations to calculate
a weight update. The optimal output of the transformer data is unknown; it’s a
hidden layer inside the network that is updated by backpropagating from output
layers.
The CuratedTransformer
component therefore does not perform a weight update
during its own update
method. Instead, it runs its transformer model and
communicates the output and the backpropagation callback to any downstream
components that have been connected to it via the transformer listener sublayer.
If there are multiple listeners, the last layer will actually backprop to the
transformer and call the optimizer, while the others simply increment the
gradients.
Name | Description |
---|---|
examples | A batch of Example objects. Only the Example.predicted Doc object is used, the reference Doc is ignored. Iterable[Example] |
keyword-only | |
drop | The dropout rate. float |
sgd | An optimizer. Will be created via create_optimizer if not set. Optional[Optimizer] |
losses | Optional record of the loss during training. Updated using the component name as the key. Optional[Dict[str, float]] |
RETURNS | The updated losses dictionary. Dict[str, float] |
CuratedTransformer.create_optimizer method
Create an optimizer for the pipeline component.
Name | Description |
---|---|
RETURNS | The optimizer. Optimizer |
CuratedTransformer.use_params methodcontextmanager
Modify the pipe’s model to use the given parameter values. At the end of the context, the original parameters are restored.
Name | Description |
---|---|
params | The parameter values to use in the model. dict |
CuratedTransformer.to_disk method
Serialize the pipe to disk.
Name | Description |
---|---|
path | A path to a directory, which will be created if it doesn’t exist. Paths may be either strings or Path -like objects. Union[str,Path] |
keyword-only | |
exclude | String names of serialization fields to exclude. Iterable[str] |
CuratedTransformer.from_disk method
Load the pipe from disk. Modifies the object in place and returns it.
Name | Description |
---|---|
path | A path to a directory. Paths may be either strings or Path -like objects. Union[str,Path] |
keyword-only | |
exclude | String names of serialization fields to exclude. Iterable[str] |
RETURNS | The modified CuratedTransformer object. CuratedTransformer |
CuratedTransformer.to_bytes method
Serialize the pipe to a bytestring.
Name | Description |
---|---|
keyword-only | |
exclude | String names of serialization fields to exclude. Iterable[str] |
RETURNS | The serialized form of the CuratedTransformer object. bytes |
CuratedTransformer.from_bytes method
Load the pipe from a bytestring. Modifies the object in place and returns it.
Name | Description |
---|---|
bytes_data | The data to load from. bytes |
keyword-only | |
exclude | String names of serialization fields to exclude. Iterable[str] |
RETURNS | The CuratedTransformer object. CuratedTransformer |
Serialization Fields
During serialization, spaCy will export several data fields used to restore
different aspects of the object. If needed, you can exclude them from
serialization by passing in the string names via the exclude
argument.
Name | Description |
---|---|
vocab | The shared Vocab . |
cfg | The config file. You usually don’t want to exclude this. |
model | The binary model data. You usually don’t want to exclude this. |
DocTransformerOutput dataclass
Curated Transformer outputs for one Doc
object. Stores the dense
representations generated by the transformer for each piece identifier. Piece
identifiers are grouped by token. Instances of this class are typically assigned
to the Doc._.trf_data
extension
attribute.
Name | Description |
---|---|
all_outputs | List of Ragged tensors that correspends to outputs of the different transformer layers. Each tensor element corresponds to a piece identifier’s representation. List[Ragged] |
last_layer_only | If only the last transformer layer’s outputs are preserved. bool |
DocTransformerOutput.embedding_layer property
Return the output of the transformer’s embedding layer or None
if
last_layer_only
is True
.
Name | Description |
---|---|
RETURNS | Embedding layer output. Optional[Ragged] |
DocTransformerOutput.last_hidden_layer_state property
Return the output of the transformer’s last hidden layer.
Name | Description |
---|---|
RETURNS | Last hidden layer output. Ragged |
DocTransformerOutput.all_hidden_layer_states property
Return the outputs of all transformer layers (excluding the embedding layer).
Name | Description |
---|---|
RETURNS | Hidden layer outputs. List[Ragged] |
DocTransformerOutput.num_outputs property
Return the number of layer outputs stored in the DocTransformerOutput
instance
(including the embedding layer).
Name | Description |
---|---|
RETURNS | Numbef of outputs. int |
Span Getters
Span getters are functions that take a batch of Doc
objects and
return a lists of Span
objects for each doc to be processed by
the transformer. This is used to manage long documents by cutting them into
smaller sequences before running the transformer. The spans are allowed to
overlap, and you can also omit sections of the Doc
if they are not relevant.
Span getters can be referenced in the
[components.transformer.model.with_spans]
block of the config to customize the
sequences processed by the transformer.
Name | Description |
---|---|
docs | A batch of Doc objects. Iterable[Doc] |
RETURNS | The spans to process by the transformer. List[List[Span]] |
WithStridedSpans.v1 registered function
Create a span getter for strided spans. If you set the window
and stride
to
the same value, the spans will cover each token once. Setting stride
lower
than window
will allow for an overlap, so that some tokens are counted twice.
This can be desirable, because it allows all tokens to have both a left and
right context.
Name | Description |
---|---|
window | The window size. int |
stride | The stride size. int |
Model Loaders
Curated Transformer models are constructed with default hyperparameters and randomized weights when the pipeline is created. To load the weights of an existing pre-trained model into the pipeline, one of the following loader callbacks can be used. The pre-trained model must have the same hyperparameters as the model used by the pipeline.
HFTransformerEncoderLoader.v1 registered_function
Construct a callback that initializes a supported transformer model with weights from a corresponding HuggingFace model.
Name | Description |
---|---|
name | Name of the HuggingFace model. str |
revision | Name of the model revision/branch. str |
PyTorchCheckpointLoader.v1 registered_function
Construct a callback that initializes a supported transformer model with weights from a PyTorch checkpoint.
Name | Description |
---|---|
path | Path to the PyTorch checkpoint. Path |
Tokenizer Loaders
Curated Transformer models must be paired with a matching tokenizer (piece encoder) model in a spaCy pipeline. As with the transformer models, tokenizers are constructed with an empty vocabulary during pipeline creation - They need to be initialized with an appropriate loader before use in training/inference.
ByteBPELoader.v1 registered_function
Construct a callback that initializes a Byte-BPE piece encoder model.
Name | Description |
---|---|
vocab_path | Path to the vocabulary file. Path |
merges_path | Path to the merges file. Path |
CharEncoderLoader.v1 registered_function
Construct a callback that initializes a character piece encoder model.
Name | Description |
---|---|
path | Path to the serialized character model. Path |
bos_piece | Piece used as a beginning-of-sentence token. Defaults to "[BOS]" . str |
eos_piece | Piece used as a end-of-sentence token. Defaults to "[EOS]" . str |
unk_piece | Piece used as a stand-in for unknown tokens. Defaults to "[UNK]" . str |
normalize | Unicode normalization form to use. Defaults to "NFKC" . str |
HFPieceEncoderLoader.v1 registered_function
Construct a callback that initializes a HuggingFace piece encoder model. Used in conjunction with the HuggingFace model loader.
Name | Description |
---|---|
name | Name of the HuggingFace model. str |
revision | Name of the model revision/branch. str |
SentencepieceLoader.v1 registered_function
Construct a callback that initializes a SentencePiece piece encoder model.
Name | Description |
---|---|
path | Path to the serialized SentencePiece model. Path |
WordpieceLoader.v1 registered_function
Construct a callback that initializes a WordPiece piece encoder model.
Name | Description |
---|---|
path | Path to the serialized WordPiece model. Path |
Callbacks
gradual_transformer_unfreezing.v1 registered_function
Construct a callback that can be used to gradually unfreeze the weights of one or more Transformer components during training. This can be used to prevent catastrophic forgetting during fine-tuning.
Name | Description |
---|---|
target_pipes | A dictionary whose keys and values correspond to the names of Transformer components and the training step at which they should be unfrozen respectively. Dict[str, int] |