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From "Fei Hu (JIRA)" <>
Subject [jira] [Created] (SYSTEMML-1831) Improve the efficiency of matrix subsetting
Date Tue, 08 Aug 2017 17:49:00 GMT
Fei Hu created SYSTEMML-1831:

             Summary: Improve the efficiency of matrix subsetting
                 Key: SYSTEMML-1831
             Project: SystemML
          Issue Type: Improvement
            Reporter: Fei Hu

For the {{rangeReIndex}} operation, it needs to read the whole input matrix into memory first
and do the subsetting in the memory. It is not efficient because it needs to read a lot of
unnecessary data, and even out of memory if the size of input matrix exceeds the available

The plan here is to read the keys in the Hadoop sequence file, and identify the keys overlapped
with the input range index. Then the values specified by the identified keys will be read.

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