Package opennlp.tools.util.eval

Class FMeasure

java.lang.Object
opennlp.tools.util.eval.FMeasure
public final class FMeasure extends Object
The FMeasure is a utility class for evaluators which measures precision, recall and the resulting f-measure.

Evaluation results are the arithmetic mean of the precision scores calculated for each reference sample and the arithmetic mean of the recall scores calculated for each reference sample.

  • Constructor Details

    • FMeasure

      public FMeasure()

  • Method Details

    • getPrecisionScore

      public double getPrecisionScore()
      Returns:
      Retrieves the arithmetic mean of the precision scores calculated for each evaluated sample.

    • getRecallScore

      public double getRecallScore()
      Returns:
      Retrieves the arithmetic mean of the recall score calculated for each evaluated sample.

    • getFMeasure

      public double getFMeasure()
      f-measure = 2 * precision * recall / (precision + recall).
      Returns:
      Retrieves the f-measure or -1 if precision + recall <= 0

    • updateScores

      public void updateScores(Object[] references, Object[] predictions)
      Updates the score based on the number of true positives and the number of predictions and references.
      Parameters:
      references - the provided references
      predictions - the predicted spans

    • mergeInto

      public void mergeInto(FMeasure measure)
      Merge results into metric.
      Parameters:
      measure - The FMeasure to merge.

    • toString

      public String toString()
      Overrides:
      toString in class Object
      Returns:
      A human-readable String representation.

    • precision

      public static double precision(Object[] references, Object[] predictions)
      Calculates the precision score for the given reference and predicted spans.
      Parameters:
      references - The gold standard spans.
      predictions - The predicted spans.
      Returns:
      The precision score or NaN if there are no predicted spans.

    • recall

      public static double recall(Object[] references, Object[] predictions)
      Calculates the recall score for the given reference and predicted spans.
      Parameters:
      references - The gold standard spans
      predictions - The predicted spans
      Returns:
      The recall score or NaN if there are no reference spans.