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  1. Mahout
  2. MAHOUT-1396

Accidental use of commons-math won't work with next Hadoop 2 release

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 0.8
    • Fix Version/s: 0.9
    • Component/s: Classification
    • Labels:
      None

      Description

      The project uses commons-math3, since about a year ago. However there is a use of old commons-math (2.2) lurking:

      core/src/main/java/org/apache/mahout/classifier/sgd/TPrior.java:
      import org.apache.commons.math.special.Gamma;

      This happens to have worked since commons-math has been pulled in by hadoop-common. But it no longer is in HEAD:

      http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-common-project/hadoop-common/pom.xml?view=markup

      So this will no longer compile against the latest Hadoop. I believe it will also not actually run again the latest Hadoop, even if one were to use a version compiled versus older Hadoop 2, since the class that uses it is used in the context of Writables – that is, outside the client environment that might happen to have packaged commons-math – and so would fail on the cluster.

      The change is trivial, to import the commons-math3 class. I've verified that tests pass and a patch is attached.

      Question is how much of a 'blocker' this should be for the pending release. It would cause it to stop working with the next Hadoop 2 release, so would be useful to get in, IMHO.

        Attachments

        1. MAHOUT-1396.patch
          0.6 kB
          Sean R. Owen

          Activity

            People

            • Assignee:
              smarthi Suneel Marthi
              Reporter:
              srowen Sean R. Owen
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