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https://issues.apache.org/jira/browse/FLINK-1901?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14708886#comment-14708886
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ASF GitHub Bot commented on FLINK-1901:
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Github user sachingoel0101 commented on the pull request:
https://github.com/apache/flink/pull/949#issuecomment-134070592
Hey @ChengXiangLi, I have another concern, regarding the seed for sampling.
It doesn't seem to serve its purpose. I tried sampling with fraction three
times with the same seed, however, every time I get different results.
I've been stuck on this problem myself for quite some time. The fix is,
instead of `seed + index`, you should just use `seed`. But then, the sample is
not truly random. Far as I could figure out, splits of data don't arrive at the
exactly same index subtask every time.
> Create sample operator for Dataset
> ----------------------------------
>
> Key: FLINK-1901
> URL: https://issues.apache.org/jira/browse/FLINK-1901
> Project: Flink
> Issue Type: Improvement
> Components: Core
> Reporter: Theodore Vasiloudis
> Assignee: Chengxiang Li
>
> In order to be able to implement Stochastic Gradient Descent and a number of
> other machine learning algorithms we need to have a way to take a random
> sample from a Dataset.
> We need to be able to sample with or without replacement from the Dataset,
> choose the relative or exact size of the sample, set a seed for
> reproducibility, and support sampling within iterations.
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