GitHub user johnnywalleye opened a pull request:
https://github.com/apache/spark/pull/1316
fix bin offset in DecisionTree node aggregations
Hi, this pull fixes (what I believe to be) a bug in DecisionTree.scala.
In the extractLeftRightNodeAggregates function, the first set of
rightNodeAgg values for Regression are set in line 792 as follows:
rightNodeAgg(featureIndex)(2 * (numBins - 2))
= binData(shift + (2 * numBins - 1)))
Then there is a loop that sets the rest of the values, as in line 809:
rightNodeAgg(featureIndex)(2 * (numBins - 2 - splitIndex)) =
binData(shift + (2 *(numBins - 2 - splitIndex))) +
rightNodeAgg(featureIndex)(2 * (numBins - 1 - splitIndex))
But since splitIndex starts at 1, this ends up skipping a set of binData
values.
The changes here address this issue, for both the Regression and
Classification cases.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/johnnywalleye/spark master
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/1316.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 #1316
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commit 73809dae4e02e1cf1e8a8c67fff1cf07376d8e15
Author: johnnywalleye <[email protected]>
Date: 2014-07-07T14:04:22Z
fix bin offset in DecisionTree node aggregations
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