[
https://issues.apache.org/jira/browse/SPARK-11581?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Joseph K. Bradley resolved SPARK-11581.
---------------------------------------
Resolution: Fixed
Fix Version/s: 1.4.2
1.6.0
1.5.3
Issue resolved by pull request 9560
[https://github.com/apache/spark/pull/9560]
> Example mllib code in documentation incorrectly computes MSE
> ------------------------------------------------------------
>
> Key: SPARK-11581
> URL: https://issues.apache.org/jira/browse/SPARK-11581
> Project: Spark
> Issue Type: Bug
> Components: Documentation
> Affects Versions: 1.3.1, 1.4.1, 1.5.1, 1.6.0
> Reporter: Brian Webb
> Priority: Trivial
> Labels: starter
> Fix For: 1.5.3, 1.6.0, 1.4.2
>
>
> The example Java code at the bottom of the mllib-decision-tree web page shows
> how to compute MSE on the test data. However, there is a bug in the code. The
> code currently divides by data.count(), but it should instead divide by the
> count of testData, testData.count().
> http://spark.apache.org/docs/latest/mllib-decision-tree.html
> Double testMSE =
> predictionAndLabel.map(new Function<Tuple2<Double, Double>, Double>() {
> @Override
> public Double call(Tuple2<Double, Double> pl) {
> Double diff = pl._1() - pl._2();
> return diff * diff;
> }
> }).reduce(new Function2<Double, Double, Double>() {
> @Override
> public Double call(Double a, Double b) {
> return a + b;
> }
> }) / data.count();
> System.out.println("Test Mean Squared Error: " + testMSE);
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org
For additional commands, e-mail: issues-h...@spark.apache.org
