GitHub user tlisonbee opened a pull request:
https://github.com/apache/flink/pull/1859
[FLINK-3664] Create method to easily summarize a DataSet of Tuples
Adding summarize() method in DataSetUtils that will supply a number of
single pass statistics for DataSets of Tuples.
Summary statistics depend on the type being summarized:
- Numeric types (Integer, IntValue, Float, Double, etc): min, max, mean,
variance, standard deviation, NaN count, Infinity count, totalCount, etc.
- String, StringValue: minLength, maxLength, meanLength, emptyCount,
totalCount
- Boolean, BooleanValue: trueCount, falseCount, totalCount.
Example usage:
`Dataset<Tuple3<Double, String, Boolean>> input = // [...]`
`Tuple3<NumericColumnSummary,StringColumnSummary, BooleanColumnSummary>
summary = DataSetUtils.summarize(input)`
`summary.f0.getStandardDeviation()`
`summary.f1.getMaxLength()`
Uses the Kahan summation algorithm to avoid numeric instability. The
algorithm is described in: "Scalable and Numerically Stable Descriptive
Statistics in SystemML", Tian et al, International Conference on Data
Engineering 2012.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/tlisonbee/flink FLINK-3664c
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/1859.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 #1859
----
commit 59e6ebad797fcbb4a81530dd75542f1ea65ae61e
Author: Todd Lisonbee <todd.lison...@intel.com>
Date: 2016-04-06T09:44:53Z
[FLINK-3664] Create DataSetUtils method to easily summarize a DataSet of
Tuples
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