microsoft/SynapseML

NullPointerException while compute accuracy with ComputeModelStatistics

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#736 opened on Nov 13, 2019

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 (7 comments) (0 reactions) (1 assignee)Scala (5,228 stars) (861 forks)batch import
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Description

Version

com.microsoft.ml.spark:mmlspark_2.11:jar:0.18.1
spark= 2.4.3
scala=2.11.12

data (csv with header) https://gist.github.com/ttpro1995/69051647a256af912803c9a16040f43a

download data and save as csv file, put into folder /data/public/HIGGS/higgs.test.predictioncsv

val data = spark.read.option("header","true").option("inferSchema", "true").csv("/data/public/HIGGS/higgs.test.predictioncsv")

Schema

root
 |-- label: double (nullable = true)
 |-- prediction: double (nullable = true)

Code

import com.microsoft.ml.spark.train.ComputeModelStatistics
val metricsCompute = new ComputeModelStatistics().setLabelCol("label").setScoresCol("prediction").setEvaluationMetric("accuracy")

val result_metrics = metricsCompute.transform(data)

Exception

java.lang.NullPointerException
  at org.apache.spark.sql.Column.<init>(Column.scala:135)
  at org.apache.spark.sql.Column$.apply(Column.scala:38)
  at org.apache.spark.sql.functions$.col(functions.scala:90)
  at com.microsoft.ml.spark.train.ComputeModelStatistics.selectAndCastToDF(ComputeModelStatistics.scala:256)
  at com.microsoft.ml.spark.train.ComputeModelStatistics.selectAndCastToRDD(ComputeModelStatistics.scala:265)
  at com.microsoft.ml.spark.train.ComputeModelStatistics.predictionAndLabels$lzycompute$1(ComputeModelStatistics.scala:99)
  at com.microsoft.ml.spark.train.ComputeModelStatistics.predictionAndLabels$1(ComputeModelStatistics.scala:95)
  at com.microsoft.ml.spark.train.ComputeModelStatistics.transform(ComputeModelStatistics.scala:124)
  ... 47 elided

Contributor guide

Tech stack
scalasparkrest api
Domain
machine learningdatabackend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
ScalaSpark DataFrame APIdebugging NullPointerException
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the code at ComputeModelStatistics.scala, specifically the selectAndCastToDF method around line 256. The NullPointerException occurs at Column.scala:135, likely due to a null column or schema mismatch. Check if null values in the prediction column or incorrect column names cause the issue. Also, examine the transform method and the predictionAndLabels computation to understand the data flow. Look for any existing fixes or related PRs in the repository.