PercentileAggregator

A PercentileAggregator is an Aggregator that determines and returns the xth percentile of the numeric property values. The percentile value is a decimal number from 0.0 to 1.0, and it must be a constant number. If no values were encountered, then the percentile value is NaN. If the percentile value does not fall directly on one particular value, then linear interpolation is used to determine the percentile value. This means that it is possible for the percentile value not to come from the list of all values. This Aggregator overrides the terminateDoubleDouble method, so that the percentile value is also available as a DoubleDouble. This allows the percentile value to be used by other Aggregators as a high-precision DoubleDouble.

Usage

Create and use a PercentileAggregator, with one of the following methods:

  • Aggregator agg = new PercentileAggregator(percentile, "property");
  • Aggregator agg = new PercentileAggregator(0.5, "property");
  • Aggregator agg = Aggregator.getAggregator("Percentile(0.75, property)");
  • Aggregator agg = Aggregator.getAggregator("Percentile(" + percentile + ", property)");

The values returned by the property of the object must be numeric.

If the given percentile maps directly to one particular value, then that value is used. Else, if the percentile maps somewhere in between two consecutive values, then linear interpolation is used to calculate the result.