sparknlp.annotator.embeddings.bert_embeddings#

Contains classes for BertEmbeddings.

Module Contents#

Classes#

BertEmbeddings

Token-level embeddings using BERT.

class BertEmbeddings(classname='com.johnsnowlabs.nlp.embeddings.BertEmbeddings', java_model=None)[source]#

Token-level embeddings using BERT.

BERT (Bidirectional Encoder Representations from Transformers) provides dense vector representations for natural language by using a deep, pre-trained neural network with the Transformer architecture.

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

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

The default model is "small_bert_L2_768", if no name is provided.

For available pretrained models please see the Models Hub.

For extended examples of usage, see the Spark NLP Workshop. 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 False

maxSentenceLength

Max sentence length to process, by default 128

configProtoBytes

ConfigProto from tensorflow, serialized into byte array.

References

BERT: Pre-training of Deep Bidirectional Transformers for Language Understanding

https://github.com/google-research/bert

Paper abstract

We introduce a new language representation model called BERT, which stands for Bidirectional Encoder Representations from Transformers. Unlike recent language representation models, BERT is designed to pre-train deep bidirectional representations from unlabeled text by jointly conditioning on both left and right context in all layers. As a result, the pre-trained BERT model can be fine-tuned with just one additional output layer to create state-of-the-art models for a wide range of tasks, such as question answering and language inference, without substantial task-specific architecture modifications. BERT is conceptually simple and empirically powerful. It obtains new state-of-the-art results on eleven natural language processing tasks, including pushing the GLUE score to 80.5% (7.7% point absolute improvement), MultiNLI accuracy to 86.7% (4.6% absolute improvement), SQuAD v1.1 question answering Test F1 to 93.2 (1.5 point absolute improvement) and SQuAD v2.0 Test F1 to 83.1 (5.1 point absolute improvement).

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 = BertEmbeddings.pretrained("small_bert_L2_128", "en") \
...     .setInputCols(["token", "document"]) \
...     .setOutputCol("bert_embeddings")
>>> embeddingsFinisher = EmbeddingsFinisher() \
...     .setInputCols(["bert_embeddings"]) \
...     .setOutputCols("finished_embeddings") \
...     .setOutputAsVector(True)
>>> 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|
+--------------------------------------------------------------------------------+
|[-2.3497989177703857,0.480538547039032,-0.3238905668258667,-1.612930893898010...|
|[-2.1357314586639404,0.32984697818756104,-0.6032363176345825,-1.6791689395904...|
|[-1.8244884014129639,-0.27088963985443115,-1.059438943862915,-0.9817547798156...|
|[-1.1648050546646118,-0.4725411534309387,-0.5938255786895752,-1.5780693292617...|
|[-0.9125322699546814,0.4563939869403839,-0.3975459933280945,-1.81611204147338...|
+--------------------------------------------------------------------------------+
name = BertEmbeddings[source]#
maxSentenceLength[source]#
configProtoBytes[source]#
setConfigProtoBytes(self, b)[source]#

Sets configProto from tensorflow, serialized into byte array.

Parameters:
bList[int]

ConfigProto from tensorflow, serialized into byte array

setMaxSentenceLength(self, value)[source]#

Sets max sentence length to process.

Parameters:
valueint

Max sentence length to process

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:
BertEmbeddings

The restored model

static pretrained(name='small_bert_L2_768', lang='en', remote_loc=None)[source]#

Downloads and loads a pretrained model.

Parameters:
namestr, optional

Name of the pretrained model, by default “small_bert_L2_768”

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:
BertEmbeddings

The restored model