Core Server
  1. Core Server
  2. SERVER-5044

$stdDev aggregation operator for standard deviation

      Details

      • Backport:
        No
      • # Replies:
        8
      • Last comment by Customer:
        true
      • Driver changes needed?:
        Driver changes needed

        Description

        see https://gist.github.com/1886960 for an algorithm to handle calculating standard deviation and variance across many servers.

          Issue Links

          links to

          Web Link https://github.com/mongodb/mongo/pull/464

          Web Link Pull request mongo/pull/409

            Activity

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            • Comments
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            Chris Westin             added a comment -

            I'm assuming this is meant to be for $group.

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            Chris Westin             added a comment - I'm assuming this is meant to be for $group.
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            Mathias Stearn             added a comment -

            Correct.

            Ideally any $group op should be usable in a $project against an array field, but that is a different issue.

            Show
            Mathias Stearn             added a comment - Correct. Ideally any $group op should be usable in a $project against an array field, but that is a different issue.
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            Justin             added a comment -

            I started this today. Here is the commit in github. https://github.com/base698/mongo/commit/2f9ab97ffb6f027faf4c503ba4a58e500eb6fb23

            It needs tests and variance. It probably could be refactored to do average, variance and standard deviation in one motion since you have to do it incrementally.

            Show
            Justin             added a comment - I started this today. Here is the commit in github. https://github.com/base698/mongo/commit/2f9ab97ffb6f027faf4c503ba4a58e500eb6fb23 It needs tests and variance. It probably could be refactored to do average, variance and standard deviation in one motion since you have to do it incrementally.
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            Matt Kangas             added a comment -

            Closed https://github.com/mongodb/mongo/pull/409 due to inactivity

            Show
            Matt Kangas             added a comment - Closed https://github.com/mongodb/mongo/pull/409 due to inactivity
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            Ranjith Ramachandra             added a comment -

            Any idea if this will be picked up at all?

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            Ranjith Ramachandra             added a comment - Any idea if this will be picked up at all?
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            Michael Svendsen             added a comment -

            I opened a pull request for this today. https://github.com/mongodb/mongo/pull/464

            This implements standard deviation and variance calculations using the algorithm listed in the description.

            Show
            Michael Svendsen             added a comment - I opened a pull request for this today. https://github.com/mongodb/mongo/pull/464 This implements standard deviation and variance calculations using the algorithm listed in the description.
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            auto             added a comment -

            Author:

            {u'username': u'RedBeard0531', u'name': u'Mathias Stearn', u'email': u'mathias@10gen.com'}

            Message: Clean up AccumulatorAvg

            Major change is not inheriting from AccumulatorSum

            Prep for SERVER-5044 $stdDev accumulator
            Branch: master
            https://github.com/mongodb/mongo/commit/982d5d281806d470696809d11dceaa098aed4906

            Show
            auto             added a comment - Author: {u'username': u'RedBeard0531', u'name': u'Mathias Stearn', u'email': u'mathias@10gen.com'} Message: Clean up AccumulatorAvg Major change is not inheriting from AccumulatorSum Prep for SERVER-5044 $stdDev accumulator Branch: master https://github.com/mongodb/mongo/commit/982d5d281806d470696809d11dceaa098aed4906
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            Kevin Davenport             added a comment -

            This is a must have.

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            Kevin Davenport             added a comment - This is a must have.

              People

              • Votes:
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                20 Start watching this issue

                Dates

                • Created:
                  Updated:
                  Days since reply:
                  13 weeks, 6 days ago
                  Date of 1st Reply: