[GitHub] incubator-metron pull request #401: METRON-637: Add a STATS_BIN function to ...

[mmiklavc <gi...@git.apache.org>]

Github user mmiklavc commented on a diff in the pull request:

    https://github.com/apache/incubator-metron/pull/401#discussion_r95368025
  
    --- Diff: metron-analytics/metron-statistics/src/main/java/org/apache/metron/statistics/StellarStatisticsFunctions.java ---
    @@ -425,4 +428,57 @@ public Object apply(List<Object> args) {
           return result;
         }
       }
    +
    +  /**
    +   * Calculates the statistical bin that a value falls in.
    +   */
    +  @Stellar(namespace = "STATS", name = "BIN"
    +          , description = "Computes the bin that the value is in based on the statistical distribution."
    +          , params = {
    +          "stats - The Stellar statistics object"
    +          , "value - The value to bin"
    +          , "bounds? - A list of percentile bin bounds (excluding min and max) or a string representing a known and common set of bins.  " +
    +          "For convenience, we have provided QUARTILE, QUINTILE, and DECILE which you can pass in as a string arg." +
    +          " If this argument is omitted, then we assume a Quartile bin split."
    +                    }
    +          ,returns = "Which bin N the value falls in such that bound(N-1) < value <= bound(N). " +
    +          "No min and max bounds are provided, so values smaller than the 0'th bound go in the 0'th bin, " +
    +          "and values greater than the last bound go in the M'th bin."
    +  )
    +  public static class StatsBin extends BaseStellarFunction {
    +    public enum BinSplits {
    +      QUARTILE(ImmutableList.of(25.0, 50.0, 75.0)),
    +      QUINTILE(ImmutableList.of(20.0, 40.0, 60.0, 80.0)),
    +      DECILE(ImmutableList.of(10.0, 20.0, 30.0, 40.0, 50.0, 60.0, 70.0, 80.0, 90.0))
    +      ;
    +      public final List<Number> split;
    +      BinSplits(List<Number> split) {
    +        this.split = split;
    +      }
    +
    +      public static List<Number> getSplit(Object o) {
    +        if(o instanceof String) {
    +          return BinSplits.valueOf((String)o).split;
    +        }
    +        else if(o instanceof List) {
    +          return ConversionUtils.convert(o, List.class);
    +        }
    +        throw new IllegalStateException("The split you tried to pass is not a valid split: " + o.toString());
    +      }
    +    }
    +
    +
    +    @Override
    +    public Object apply(List<Object> args) {
    +      StatisticsProvider stats = convert(args.get(0), StatisticsProvider.class);
    +      Double value = convert(args.get(1), Double.class);
    +      final List<Number> bins = args.size() > 2?BinSplits.getSplit(args.get(2)):BinSplits.QUARTILE.split;
    +
    +      if (stats == null || value == null || bins.size() == 0) {
    +        return -1;
    +      }
    +      return MathFunctions.Bin.getBin(value, bins.size(), bin -> stats.getPercentile(bins.get(bin).doubleValue()));
    --- End diff --
    
    Nice suggestion by Matt. And I like the math bin code reuse and ability to plug in a stats function provider.


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