[英]How to evaluate the performance of the model (accuracy) in Spark Pipeline with Linear Regression
嘗試使用線性回歸運行 Spark 管道,我能夠執行模型,並尋找
import org.apache.spark.ml.feature.VectorAssembler
import spark.implicits._
import org.apache.spark.sql
import org.apache.spark.sql.functions._
import org.apache.spark.sql.types.DecimalType
import org.apache.spark.sql.{Dataset, Row, SparkSession}
import org.apache.spark.ml.regression.LinearRegression
import org.apache.spark.ml.feature.OneHotEncoderEstimator
import org.apache.spark.ml.{Pipeline, PipelineModel}
val splitDF: Array[Dataset[Row]] = inputDF.randomSplit(Array(0.5, 0.5))
val trainingDF = splitDF(0)
val testingDF = splitDF(1)
val encoder = new OneHotEncoderEstimator()
.setInputCols(Array("_LookUpID"))
.setOutputCols(Array("_LookUpID_Encoded"))
val requiredFeatures = Array("_LookUpID_Encoded","VALUE1")
val assembler = new VectorAssembler()
.setInputCols(requiredFeatures)
.setOutputCol("features")
val lr = new LinearRegression()
.setMaxIter(10)
.setRegParam(0.3)
.setElasticNetParam(0.8)
.setFeaturesCol("features")
.setLabelCol("VALUE2")
// Fit the model
val pipeline = new Pipeline()
.setStages(Array(encoder, assembler, lr))
// Fit the pipeline to training documents.
val lrModel = pipeline.fit(trainingDF)
val predictions = lrModel.transform(testingDF)
println("*** Predictions ***")
predictions.printSchema()
predictions.select("VALUE_DATE","_LookUpID","_CD","VALUE1","VALUE2","prediction").show(100)
val rm = new RegressionMetrics(predictions.rdd.map(x => (x(4).asInstanceOf[Double], x(5).asInstanceOf[Double])))
println("sqrt(MSE): " + Math.sqrt(rm.meanSquaredError))
println("R Squared: " + rm.r2)
println("Explained Variance: " + rm.explainedVariance + "\n")
使用分區攝取
def getDataFrame(sql: String, lowerNumber: Int, upperNumber: Int): DataFrame = {
val inputDF: DataFrame =
spark.read.format(source = "jdbc")
.option("url", "jdbc:oracle:thin:@//url")
.option("user", "user")
.option("password", "password")
.option("driver", "oracle.jdbc.OracleDriver")
.option("dbtable", s"($sql)")
.option("partitionColumn", "_LookUpID")
.option("numPartitions", "6")
.option("lowerBound", lowerNumber)
.option("upperBound", upperNumber)
.load()
inputDF
}
謝謝
使用 RegressionMetrics更新問題以獲取指標的 RMSE 和 R Squared 等
分區數據集並增加驅動程序的堆內存,暫時解決了內存問題。 會持續監控
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