apache-spark - 线性回归 scala.MatchError :

Question

在 Spark 1.6.1 和 2.0 中使用 ParamGridBuilder 时出现 scala.MatchError

val paramGrid = new ParamGridBuilder()
  .addGrid(lr.regParam, Array(0.1, 0.01))
  .addGrid(lr.fitIntercept)
  .addGrid(lr.elasticNetParam, Array(0.0, 0.5, 1.0))
  .build()

错误是

org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 57.0 failed 1 times, most recent failure: Lost task 0.0 in stage 57.0 (TID 257, localhost): 
scala.MatchError: [280000,1.0,[2400.0,9373.0,3.0,1.0,1.0,0.0,0.0,0.0]] (of class org.apache.spark.sql.catalyst.expressions.GenericRowWithSchema)

Full code

问题是在这种情况下我应该如何使用 ParamGridBuilder

Answer 1

这里的问题是输入模式而不是 ParamGridBuilder。价格列作为整数加载，而 LinearRegression 预期为 double 。您可以通过将列显式转换为所需类型来修复它:

val houses = sqlContext.read.format("com.databricks.spark.csv")
  .option("header", "true")
  .option("inferSchema", "true")
  .load(...)
  .withColumn("price", $"price".cast("double"))