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From sounakr <...@git.apache.org>
Subject [GitHub] carbondata pull request #1763: [CARBONDATA-1984] Double Compression Codec Re...
Date Thu, 04 Jan 2018 10:36:58 GMT
GitHub user sounakr opened a pull request:

    https://github.com/apache/carbondata/pull/1763

    [CARBONDATA-1984] Double Compression Codec Rectification.

    
    Double datatype compression done through AdaptiveFloatingDelta AdaptiveFloating codec
is not returning expected output. These two codec for double compression multiple double with
another double. Double multipled with double doesnt give exact output, 1.2 ie one-and-one-fifth
can't be exactly represented as a binary fraction. You get close with one-and-an-eigth-and-a-sixteenth....
but never exactly one-fifth. 
    
    So due to the multiply and substract to encode the data, there are some loss of precision
and we give a different output when encoded. 
    
     - [ ] Any interfaces changed? No
     
     - [ ] Any backward compatibility impacted? No
     
     - [ ] Document update required? No
    
     - [ ] Testing done Yes
            Please provide details on 
            - Whether new unit test cases have been added or why no new tests are required?
            - How it is tested? Please attach test report.
            - Is it a performance related change? Please attach the performance test report.
            - Any additional information to help reviewers in testing this change.
           
     - [ ] For large changes, please consider breaking it into sub-tasks under an umbrella
JIRA. NA
    


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

    $ git pull https://github.com/sounakr/incubator-carbondata double_datatype_roundoff

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

    https://github.com/apache/carbondata/pull/1763.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 #1763
    
----
commit 6ede959fef92c017818755e6be311b0794e3566d
Author: sounakr <sounakr@...>
Date:   2018-01-04T09:45:42Z

    [CARBONDATA-1984] Double Compression Codec Rectification. Use RoundUp in case double is
multipled with double to get consistant result.

----


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