sparknlp.annotator.LongformerEmbeddings

class sparknlp.annotator.LongformerEmbeddings(classname='com.johnsnowlabs.nlp.embeddings.LongformerEmbeddings', java_model=None)[source]

Bases: sparknlp.common.AnnotatorModel, sparknlp.common.HasEmbeddingsProperties, sparknlp.common.HasCaseSensitiveProperties, sparknlp.common.HasStorageRef, sparknlp.common.HasBatchedAnnotate

Longformer is a transformer model for long documents. The Longformer model was presented in Longformer: The Long-Document Transformer by Iz Beltagy, Matthew E. Peters, Arman Cohan. longformer-base-4096 is a BERT-like model started from the RoBERTa checkpoint and pretrained for MLM on long documents. It supports sequences of length up to 4,096.

Pretrained models can be loaded with pretrained() of the companion object:

>>> embeddings = LongformerEmbeddings.pretrained() \
...     .setInputCols(["document", "token"]) \
...     .setOutputCol("embeddings")

The default model is "longformer_base_4096", if no name is provided. For available pretrained models please see the Models Hub.

Models from the HuggingFace 🤗 Transformers library are compatible with Spark NLP 🚀. To see which models are compatible and how to import them see Import Transformers into Spark NLP 🚀.

Input Annotation types

Output Annotation type

DOCUMENT, TOKEN

WORD_EMBEDDINGS

Parameters
batchSize

Size of every batch, by default 8

dimension

Number of embedding dimensions, by default 768

caseSensitive

Whether to ignore case in tokens for embeddings matching, by default True

maxSentenceLength

Max sentence length to process, by default 1024

configProtoBytes

ConfigProto from tensorflow, serialized into byte array.

References

Longformer: The Long-Document Transformer

Paper Abstract:

Transformer-based models are unable to process long sequences due to their self-attention operation, which scales quadratically with the sequence length. To address this limitation, we introduce the Longformer with an attention mechanism that scales linearly with sequence length, making it easy to process documents of thousands of tokens or longer. Longformer’s attention mechanism is a drop-in replacement for the standard self-attention and combines a local windowed attention with a task motivated global attention. Following prior work on long-sequence transformers, we evaluate Longformer on character-level language modeling and achieve state-of-the-art results on text8 and enwik8. In contrast to most prior work, we also pretrain Longformer and finetune it on a variety of downstream tasks. Our pretrained Longformer consistently outperforms RoBERTa on long document tasks and sets new state-of-the-art results on WikiHop and TriviaQA. We finally introduce the Longformer-Encoder-Decoder (LED), a Longformer variant for supporting long document generative sequence-to-sequence tasks, and demonstrate its effectiveness on the arXiv summarization dataset.

The original code can be found at Longformer: The Long-Document Transformer.

Examples

>>> import sparknlp
>>> from sparknlp.base import *
>>> from sparknlp.annotator import *
>>> from pyspark.ml import Pipeline
>>> documentAssembler = DocumentAssembler() \
...     .setInputCol("text") \
...     .setOutputCol("document")
>>> tokenizer = Tokenizer() \
...     .setInputCols(["document"]) \
...     .setOutputCol("token")
>>> embeddings = LongformerEmbeddings.pretrained() \
...     .setInputCols(["document", "token"]) \
...     .setOutputCol("embeddings") \
...     .setCaseSensitive(True)
>>> embeddingsFinisher = EmbeddingsFinisher() \
>>>     .setInputCols(["embeddings"]) \
...     .setOutputCols("finished_embeddings") \
...     .setOutputAsVector(True) \
...     .setCleanAnnotations(False)
>>> pipeline = Pipeline() \
...     .setStages([
...         documentAssembler,
...         tokenizer,
...         embeddings,
...         embeddingsFinisher
...     ])
>>> data = spark.createDataFrame([["This is a sentence."]]).toDF("text")
>>> result = pipeline.fit(data).transform(data)
>>> result.selectExpr("explode(finished_embeddings) as result").show(5, 80)
+--------------------------------------------------------------------------------+
|                                                                          result|
+--------------------------------------------------------------------------------+
|[0.18792399764060974,-0.14591649174690247,0.20547787845134735,0.1468472778797...|
|[0.22845706343650818,0.18073144555091858,0.09725798666477203,-0.0417917296290...|
|[0.07037967443466187,-0.14801117777824402,-0.03603338822722435,-0.17893412709...|
|[-0.08734266459941864,0.2486150562763214,-0.009067727252840996,-0.24408400058...|
|[0.22409197688102722,-0.4312366545200348,0.1401449590921402,0.356410235166549...|
+--------------------------------------------------------------------------------+

Methods

__init__([classname, java_model])

Initialize this instance with a Java model object.

clear(param)

Clears a param from the param map if it has been explicitly set.

copy([extra])

Creates a copy of this instance with the same uid and some extra params.

explainParam(param)

Explains a single param and returns its name, doc, and optional default value and user-supplied value in a string.

explainParams()

Returns the documentation of all params with their optionally default values and user-supplied values.

extractParamMap([extra])

Extracts the embedded default param values and user-supplied values, and then merges them with extra values from input into a flat param map, where the latter value is used if there exist conflicts, i.e., with ordering: default param values < user-supplied values < extra.

getBatchSize()

Gets current batch size.

getCaseSensitive()

Gets whether to ignore case in tokens for embeddings matching.

getDimension()

Gets embeddings dimension.

getInputCols()

Gets current column names of input annotations.

getLazyAnnotator()

Gets whether Annotator should be evaluated lazily in a RecursivePipeline.

getOrDefault(param)

Gets the value of a param in the user-supplied param map or its default value.

getOutputCol()

Gets output column name of annotations.

getParam(paramName)

Gets a param by its name.

getParamValue(paramName)

Gets the value of a parameter.

getStorageRef()

Gets unique reference name for identification.

hasDefault(param)

Checks whether a param has a default value.

hasParam(paramName)

Tests whether this instance contains a param with a given (string) name.

isDefined(param)

Checks whether a param is explicitly set by user or has a default value.

isSet(param)

Checks whether a param is explicitly set by user.

load(path)

Reads an ML instance from the input path, a shortcut of read().load(path).

loadSavedModel(folder, spark_session)

Loads a locally saved model.

pretrained([name, lang, remote_loc])

Downloads and loads a pretrained model.

read()

Returns an MLReader instance for this class.

save(path)

Save this ML instance to the given path, a shortcut of 'write().save(path)'.

set(param, value)

Sets a parameter in the embedded param map.

setBatchSize(v)

Sets batch size.

setCaseSensitive(value)

Sets whether to ignore case in tokens for embeddings matching.

setConfigProtoBytes(b)

Sets configProto from tensorflow, serialized into byte array.

setDimension(value)

Sets embeddings dimension.

setInputCols(*value)

Sets column names of input annotations.

setLazyAnnotator(value)

Sets whether Annotator should be evaluated lazily in a RecursivePipeline.

setMaxSentenceLength(value)

Sets max sentence length to process, by default 1024.

setOutputCol(value)

Sets output column name of annotations.

setParamValue(paramName)

Sets the value of a parameter.

setParams()

setStorageRef(value)

Sets unique reference name for identification.

transform(dataset[, params])

Transforms the input dataset with optional parameters.

write()

Returns an MLWriter instance for this ML instance.

Attributes

batchSize

caseSensitive

configProtoBytes

dimension

getter_attrs

inputCols

lazyAnnotator

maxSentenceLength

name

outputCol

params

Returns all params ordered by name.

storageRef

clear(param)

Clears a param from the param map if it has been explicitly set.

copy(extra=None)

Creates a copy of this instance with the same uid and some extra params. This implementation first calls Params.copy and then make a copy of the companion Java pipeline component with extra params. So both the Python wrapper and the Java pipeline component get copied.

Parameters

extra – Extra parameters to copy to the new instance

Returns

Copy of this instance

explainParam(param)

Explains a single param and returns its name, doc, and optional default value and user-supplied value in a string.

explainParams()

Returns the documentation of all params with their optionally default values and user-supplied values.

extractParamMap(extra=None)

Extracts the embedded default param values and user-supplied values, and then merges them with extra values from input into a flat param map, where the latter value is used if there exist conflicts, i.e., with ordering: default param values < user-supplied values < extra.

Parameters

extra – extra param values

Returns

merged param map

getBatchSize()

Gets current batch size.

Returns
int

Current batch size

getCaseSensitive()

Gets whether to ignore case in tokens for embeddings matching.

Returns
bool

Whether to ignore case in tokens for embeddings matching

getDimension()

Gets embeddings dimension.

getInputCols()

Gets current column names of input annotations.

getLazyAnnotator()

Gets whether Annotator should be evaluated lazily in a RecursivePipeline.

getOrDefault(param)

Gets the value of a param in the user-supplied param map or its default value. Raises an error if neither is set.

getOutputCol()

Gets output column name of annotations.

getParam(paramName)

Gets a param by its name.

getParamValue(paramName)

Gets the value of a parameter.

Parameters
paramNamestr

Name of the parameter

getStorageRef()

Gets unique reference name for identification.

Returns
str

Unique reference name for identification

hasDefault(param)

Checks whether a param has a default value.

hasParam(paramName)

Tests whether this instance contains a param with a given (string) name.

isDefined(param)

Checks whether a param is explicitly set by user or has a default value.

isSet(param)

Checks whether a param is explicitly set by user.

classmethod load(path)

Reads an ML instance from the input path, a shortcut of read().load(path).

static loadSavedModel(folder, spark_session)[source]

Loads a locally saved model.

Parameters
folderstr

Folder of the saved model

spark_sessionpyspark.sql.SparkSession

The current SparkSession

Returns
LongformerEmbeddings

The restored model

property params

Returns all params ordered by name. The default implementation uses dir() to get all attributes of type Param.

static pretrained(name='longformer_base_4096', lang='en', remote_loc=None)[source]

Downloads and loads a pretrained model.

Parameters
namestr, optional

Name of the pretrained model, by default “longformer_base_4096”

langstr, optional

Language of the pretrained model, by default “en”

remote_locstr, optional

Optional remote address of the resource, by default None. Will use Spark NLPs repositories otherwise.

Returns
LongformerEmbeddings

The restored model

classmethod read()

Returns an MLReader instance for this class.

save(path)

Save this ML instance to the given path, a shortcut of ‘write().save(path)’.

set(param, value)

Sets a parameter in the embedded param map.

setBatchSize(v)

Sets batch size.

Parameters
vint

Batch size

setCaseSensitive(value)

Sets whether to ignore case in tokens for embeddings matching.

Parameters
valuebool

Whether to ignore case in tokens for embeddings matching

setConfigProtoBytes(b)[source]

Sets configProto from tensorflow, serialized into byte array.

Parameters
bList[str]

ConfigProto from tensorflow, serialized into byte array

setDimension(value)

Sets embeddings dimension.

Parameters
valueint

Embeddings dimension

setInputCols(*value)

Sets column names of input annotations.

Parameters
*valuestr

Input columns for the annotator

setLazyAnnotator(value)

Sets whether Annotator should be evaluated lazily in a RecursivePipeline.

Parameters
valuebool

Whether Annotator should be evaluated lazily in a RecursivePipeline

setMaxSentenceLength(value)[source]

Sets max sentence length to process, by default 1024.

Parameters
valueint

Max sentence length to process

setOutputCol(value)

Sets output column name of annotations.

Parameters
valuestr

Name of output column

setParamValue(paramName)

Sets the value of a parameter.

Parameters
paramNamestr

Name of the parameter

setStorageRef(value)

Sets unique reference name for identification.

Parameters
valuestr

Unique reference name for identification

transform(dataset, params=None)

Transforms the input dataset with optional parameters.

Parameters
  • dataset – input dataset, which is an instance of pyspark.sql.DataFrame

  • params – an optional param map that overrides embedded params.

Returns

transformed dataset

New in version 1.3.0.

uid

A unique id for the object.

write()

Returns an MLWriter instance for this ML instance.