[jira] [Commented] (FLINK-3783) Support weighted random sampling with reservoir

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-3783?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15247254#comment-15247254 ] 

ASF GitHub Bot commented on FLINK-3783:
---------------------------------------

GitHub user gallenvara opened a pull request:

    https://github.com/apache/flink/pull/1909

    [FLINK-3783] [core] Support weighted random sampling with reservoir.

    Thanks for contributing to Apache Flink. Before you open your pull request, please take the following check list into consideration.
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    In default random sampling, all items have the same probability to be selected. But in weighted random sampling, the probability of each item to be selected is determined by its weight with respect to the weights of the other items. This is reference paper: http://arxiv.org/pdf/1012.0256.pdf. The test of WRS is defining 10 items with different probability and counting every item in the reservoir to get the probability after sampling and comparing with expected probabilities to verify its correctness. Also, the paper describe method with exponential jumps, i think we can implement it in future.
    


You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/gallenvara/flink WeightedRandomSample

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/flink/pull/1909.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #1909
    
----
commit 33b961602dd1d289a979869250b88a43c68ba9ab
Author: gallenvara <ga...@126.com>
Date:   2016-04-18T08:50:20Z

    Support weighted random sampler.

----


> Support weighted random sampling with reservoir
> -----------------------------------------------
>
>                 Key: FLINK-3783
>                 URL: https://issues.apache.org/jira/browse/FLINK-3783
>             Project: Flink
>          Issue Type: Improvement
>          Components: Core
>            Reporter: GaoLun
>            Assignee: GaoLun
>            Priority: Minor
>
> In default random sampling, all items have the same probability to be selected. But in weighted random sampling, the probability of each item to be selected is determined by its weight with respect to the weights of the other items.



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