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From "Matthias Boehm (JIRA)" <j...@apache.org>
Subject [jira] [Created] (SYSTEMML-2007) New order with multiple order-by columns
Date Mon, 06 Nov 2017 22:55:01 GMT
Matthias Boehm created SYSTEMML-2007:
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             Summary: New order with multiple order-by columns
                 Key: SYSTEMML-2007
                 URL: https://issues.apache.org/jira/browse/SYSTEMML-2007
             Project: SystemML
          Issue Type: Task
            Reporter: Matthias Boehm


There are multiple use cases, where users have to emulate an order with multiple order-by
columns as follows (which works due to stable sort):
{code}
X = order(target=X, by=3, ...)
X = order(target=X, by=2, ...)
X = order(target=X, by=1, ...)
{code}

This causes unnecessary overhead by sorting the dataset in the number of order-by columns.
Hence, this task aims to support an order function that allows both scalar and matrix {{by}}
parameters.



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