Package com.yahoo.searchlib.aggregation.hll

Class BiasEstimator

  • public class BiasEstimator
extends java.lang.Object
    Performs bias correction for a given precision and raw estimate. The values are taken from Google's HLL++ paper: https://docs.google.com/document/d/1gyjfMHy43U9OWBXxfaeG-3MjGzejW1dlpyMwEYAAWEI/view?fullscreen#
    Author:
    bjorncs

    • Constructor Summary

      Constructors 
      Constructor Description
      BiasEstimator​(int precision)
      Constructs the BiasEstimator for a given HLL precision.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      double estimateBias​(double rawEstimate)
      Maps a given raw estimate to a bias correction value.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • BiasEstimator

        public BiasEstimator​(int precision)
        Constructs the BiasEstimator for a given HLL precision.
        Parameters:
        precision - HLL precision

    • Method Detail

      • estimateBias

        public double estimateBias​(double rawEstimate)
        Maps a given raw estimate to a bias correction value. The callee should subtract the bias from the raw estimate to get a bias corrected HLL estimate. Uses linear interpolation when no exact value exist.
        Parameters:
        rawEstimate - The raw HLL estimate
        Returns:
        The estimated bias for the given raw estimate.