Word Embeddings lookup annotator that maps tokens to vectors.

For instantiated/pretrained models, see WordEmbeddingsModel.

A custom token lookup dictionary for embeddings can be set with setStoragePath. Each line of the provided file needs to have a token, followed by their vector representation, delimited by a spaces.

...
are 0.39658191506190343 0.630968081620067 0.5393722253731201 0.8428180123359783
were 0.7535235923631415 0.9699218875629833 0.10397182122983872 0.11833962569383116
stress 0.0492683418305907 0.9415954572751959 0.47624463167525755 0.16790967216778263
induced 0.1535748762292387 0.33498936903209897 0.9235178224122094 0.1158772920395934
...

If a token is not found in the dictionary, then the result will be a zero vector of the same dimension. Statistics about the rate of converted tokens, can be retrieved with WordEmbeddingsModel.withCoverageColumn and WordEmbeddingsModel.overallCoverage.

For extended examples of usage, see the Examples and the WordEmbeddingsTestSpec.

Example

In this example, the file random_embeddings_dim4.txt has the form of the content above.

import spark.implicits._
import com.johnsnowlabs.nlp.base.DocumentAssembler
import com.johnsnowlabs.nlp.annotators.Tokenizer
import com.johnsnowlabs.nlp.embeddings.WordEmbeddings
import com.johnsnowlabs.nlp.util.io.ReadAs
import com.johnsnowlabs.nlp.EmbeddingsFinisher
import org.apache.spark.ml.Pipeline

val documentAssembler = new DocumentAssembler()
  .setInputCol("text")
  .setOutputCol("document")

val tokenizer = new Tokenizer()
  .setInputCols(Array("document"))
  .setOutputCol("token")

val embeddings = new WordEmbeddings()
  .setStoragePath("src/test/resources/random_embeddings_dim4.txt", ReadAs.TEXT)
  .setStorageRef("glove_4d")
  .setDimension(4)
  .setInputCols("document", "token")
  .setOutputCol("embeddings")

val embeddingsFinisher = new EmbeddingsFinisher()
  .setInputCols("embeddings")
  .setOutputCols("finished_embeddings")
  .setOutputAsVector(true)
  .setCleanAnnotations(false)

val pipeline = new Pipeline()
  .setStages(Array(
    documentAssembler,
    tokenizer,
    embeddings,
    embeddingsFinisher
  ))

val data = Seq("The patient was diagnosed with diabetes.").toDF("text")
val result = pipeline.fit(data).transform(data)

result.selectExpr("explode(finished_embeddings) as result").show(false)
+----------------------------------------------------------------------------------+
|result                                                                            |
+----------------------------------------------------------------------------------+
|[0.9439099431037903,0.4707513153553009,0.806300163269043,0.16176554560661316]     |
|[0.7966810464859009,0.5551124811172485,0.8861005902290344,0.28284206986427307]    |
|[0.025029370561242104,0.35177749395370483,0.052506182342767715,0.1887107789516449]|
|[0.08617766946554184,0.8399239182472229,0.5395117998123169,0.7864698767662048]    |
|[0.6599600911140442,0.16109347343444824,0.6041093468666077,0.8913561105728149]    |
|[0.5955275893211365,0.01899011991918087,0.4397728443145752,0.8911281824111938]    |
|[0.9840458631515503,0.7599489092826843,0.9417727589607239,0.8624503016471863]     |
+----------------------------------------------------------------------------------+