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https://issues.apache.org/jira/browse/SPARK-3578?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14138188#comment-14138188
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Apache Spark commented on SPARK-3578:
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User 'ankurdave' has created a pull request for this issue:
https://github.com/apache/spark/pull/2439
> GraphGenerators.sampleLogNormal sometimes returns too-large result
> ------------------------------------------------------------------
>
> Key: SPARK-3578
> URL: https://issues.apache.org/jira/browse/SPARK-3578
> Project: Spark
> Issue Type: Bug
> Affects Versions: 1.2.0
> Reporter: Ankur Dave
> Assignee: Ankur Dave
> Priority: Minor
>
> GraphGenerators.sampleLogNormal is supposed to return an integer strictly
> less than maxVal. However, it violates this guarantee. It generates its
> return value as follows:
> {code}
> var X: Double = maxVal
> while (X >= maxVal) {
> val Z = rand.nextGaussian()
> X = math.exp(mu + sigma*Z)
> }
> math.round(X.toFloat)
> {code}
> When X is sampled to be close to (but less than) maxVal, then it will pass
> the while loop condition, but the rounded result will be equal to maxVal,
> which will fail the test.
> For example, if maxVal is 5 and X is 4.9, then X < maxVal, but
> math.round(X.toFloat) is 5.
> A solution is to round X down instead of to the nearest integer.
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