Package org.elasticsearch.index.query.functionscore

Interface DecayFunction

  • public interface DecayFunction
    Implement this interface to provide a decay function that is executed on a distance. For example, this could be an exponential drop of, a triangle function or something of the kind. This is used, for example, by GaussDecayFunctionBuilder.

    • Method Summary

      Modifier and Type Method Description
      double evaluate​(double value, double scale)  
      org.apache.lucene.search.Explanation explainFunction​(java.lang.String valueString, double value, double scale)  
      double processScale​(double scale, double decay)
      The final scale parameter is computed from the scale parameter given by the user and a value.

    • Method Detail

      • evaluate

        double evaluate​(double value,
                double scale)

      • explainFunction

        org.apache.lucene.search.Explanation explainFunction​(java.lang.String valueString,
                                                     double value,
                                                     double scale)

      • processScale

        double processScale​(double scale,
                    double decay)
        The final scale parameter is computed from the scale parameter given by the user and a value. This value is the value that the decay function should compute if document distance and user defined scale equal. The scale parameter for the function must be adjusted accordingly in this function
        Parameters:
        scale - the raw scale value given by the user
        decay - the value which decay function should take once the distance reaches this scale