diff --git a/mllib/src/main/scala/org/apache/spark/ml/feature/StandardScaler.scala b/mllib/src/main/scala/org/apache/spark/ml/feature/StandardScaler.scala index 1b102619b3..447851ec03 100644 --- a/mllib/src/main/scala/org/apache/spark/ml/feature/StandardScaler.scala +++ b/mllib/src/main/scala/org/apache/spark/ml/feature/StandardScaler.scala @@ -30,7 +30,22 @@ import org.apache.spark.sql.types.{StructField, StructType} /** * Params for [[StandardScaler]] and [[StandardScalerModel]]. */ -private[feature] trait StandardScalerParams extends Params with HasInputCol with HasOutputCol +private[feature] trait StandardScalerParams extends Params with HasInputCol with HasOutputCol { + + /** + * False by default. Centers the data with mean before scaling. + * It will build a dense output, so this does not work on sparse input + * and will raise an exception. + * @group param + */ + val withMean: BooleanParam = new BooleanParam(this, "withMean", "Center data with mean") + + /** + * True by default. Scales the data to unit standard deviation. + * @group param + */ + val withStd: BooleanParam = new BooleanParam(this, "withStd", "Scale to unit standard deviation") +} /** * :: AlphaComponent :: @@ -40,18 +55,27 @@ private[feature] trait StandardScalerParams extends Params with HasInputCol with @AlphaComponent class StandardScaler extends Estimator[StandardScalerModel] with StandardScalerParams { + setDefault(withMean -> false, withStd -> true) + /** @group setParam */ def setInputCol(value: String): this.type = set(inputCol, value) /** @group setParam */ def setOutputCol(value: String): this.type = set(outputCol, value) - + + /** @group setParam */ + def setWithMean(value: Boolean): this.type = set(withMean, value) + + /** @group setParam */ + def setWithStd(value: Boolean): this.type = set(withStd, value) + override def fit(dataset: DataFrame, paramMap: ParamMap): StandardScalerModel = { transformSchema(dataset.schema, paramMap, logging = true) val map = extractParamMap(paramMap) val input = dataset.select(map(inputCol)).map { case Row(v: Vector) => v } - val scaler = new feature.StandardScaler().fit(input) - val model = new StandardScalerModel(this, map, scaler) + val scaler = new feature.StandardScaler(withMean = map(withMean), withStd = map(withStd)) + val scalerModel = scaler.fit(input) + val model = new StandardScalerModel(this, map, scalerModel) Params.inheritValues(map, this, model) model }