org.apache.spark.ml.algs.ALSEstimator.scala Maven / Gradle / Ivy
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*
* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.spark.ml.algs
import org.apache.spark.ml.evaluation.Evaluator
import org.apache.spark.ml.recommendation.ALS
import org.apache.spark.ml.{BaseAlgorithmEstimator, Estimator, Model}
import org.apache.spark.sql.DataFrame
import org.apache.spark.sql.functions._
/**
* 7/27/16 WilliamZhu([email protected])
*/
class ALSEstimator(training: DataFrame, params: Array[Map[String, Any]]) extends BaseAlgorithmEstimator {
val als: ALS = new ALS()
override def source(training: DataFrame, vectorSize: Int): DataFrame = {
val t = udf { features: String =>
val Array(user, item, rank) = features.split(",")
Array(user.toInt, item.toInt, rank.toFloat)
}
training.select(
col("label"),
t(col("features"))(0) as "user",
t(col("features"))(1) as "item",
t(col("features"))(2) as "rating"
)
}
override def fit: Model[_] = {
val paramGrid = mlParams(params.tail)
val vectorSize = if (params.head.contains("dicTable")) {
training.sqlContext.table(params.head.getOrElse("dicTable", "").toString).count()
} else 0l
als.fit(source(training, vectorSize.toInt), paramGrid(0))
}
override def algorithm: Estimator[_] = als
override def evaluator: Evaluator = null
override def name: String = "als"
}