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https://issues.apache.org/jira/browse/SPARK-17086?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15426259#comment-15426259
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Sean Owen commented on SPARK-17086:
-----------------------------------
You are right, some buckets will get no values. If the input has so few
distinct (integer) values, 10 buckets is too many and there's no way 3 distinct
values can ever fall into more than 3 distinct buckets. That much is actually
fine IMHO.
But yes it's ambiguous because 2 can logically go into [2,2) or [2,3). If it
were consistently mapped into one of them, like the first matching bucket, I
think it would still be valid output. If there's no easy way to make this
mapping consistently then I agree it should probably be an error to end up with
splits like this.
(I'm also not sure why 8 splits are output in the example but 10 buckets were
requested. It just defines 7 buckets.)
> QuantileDiscretizer throws InvalidArgumentException (parameter splits given
> invalid value) on valid data
> --------------------------------------------------------------------------------------------------------
>
> Key: SPARK-17086
> URL: https://issues.apache.org/jira/browse/SPARK-17086
> Project: Spark
> Issue Type: Bug
> Components: ML
> Affects Versions: 2.1.0
> Reporter: Barry Becker
>
> I discovered this bug when working with a build from the master branch (which
> I believe is 2.1.0). This used to work fine when running spark 1.6.2.
> I have a dataframe with an "intData" column that has values like
> {code}
> 1 3 2 1 1 2 3 2 2 2 1 3
> {code}
> I have a stage in my pipeline that uses the QuantileDiscretizer to produce
> equal weight splits like this
> {code}
> new QuantileDiscretizer()
> .setInputCol("intData")
> .setOutputCol("intData_bin")
> .setNumBuckets(10)
> .fit(df)
> {code}
> But when that gets run it (incorrectly) throws this error:
> {code}
> parameter splits given invalid value [-Infinity, 1.0, 1.0, 2.0, 2.0, 3.0,
> 3.0, Infinity]
> {code}
> I don't think that there should be duplicate splits generated should there be?
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