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https://issues.apache.org/jira/browse/SPARK-6068?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14341128#comment-14341128
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Joseph K. Bradley commented on SPARK-6068:
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Yes, unit tests should not be flaky.

True, fixed seeds are a bit of a hack but have worked pretty well so far.

That would be great if you fixed the implementation to prevent low-likelihood 
failures.

> KMeans Parallel test may fail
> -----------------------------
>
>                 Key: SPARK-6068
>                 URL: https://issues.apache.org/jira/browse/SPARK-6068
>             Project: Spark
>          Issue Type: Bug
>          Components: MLlib
>    Affects Versions: 1.2.1
>            Reporter: Derrick Burns
>              Labels: clustering
>   Original Estimate: 24h
>  Remaining Estimate: 24h
>
> The test  "k-means|| initialization in KMeansSuite can fail when the random 
> number generator is truly random.
> The test is predicated on the assumption that each round of K-Means || will 
> add at least one new cluster center.  The current implementation of K-Means 
> || adds 2*k cluster centers with high probability.  However, there is no 
> deterministic lower bound on the number of cluster centers added.
> Choices are:
> 1)  change the KMeans || implementation to iterate on selecting points until 
> it has satisfied a lower bound on the number of points chosen.
> 2) eliminate the test
> 3) ignore the problem and depend on the random number generator to sample the 
> space in a lucky manner. 
> Option (1) is most in keeping with the contract that KMeans || should provide 
> a precise number of cluster centers when possible. 



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