/**
 * Copyright (c) 1995-2010, The University of Sheffield. See the file
 * COPYRIGHT.txt in the software or at http://gate.ac.uk/gate/COPYRIGHT.txt This
 * file is part of GATE (see http://gate.ac.uk/), and is free software, licenced
 * under the GNU Library General Public License, Version 2, June 1991 (in the
 * distribution as file licence.html, and also available at
 * http://gate.ac.uk/gate/licence.html). $Id: FMeasure.java 12006 2009-12-01
 * 17:24:28Z thomas_heitz $
 */
package gate.iaaplugin;

/**
 * Compute the F-measures such as Precision, Recall and F1, given the numbers of
 * correct matches, missing, and spurious. It also includes a few methods for
 * adding and averaging the F-measures and printing the results.
 */
public class FMeasure {
  /** Precision for exact matches. */
  public float precision;

  /** Recall for exact matches. */
  public float recall;

  /** F1 for exact matches. */
  public float f1;

  /** Precision for exact and partial matches. */
  public float precisionLenient;

  /** Recall for exact and partial matches. */
  public float recallLenient;

  /** F1 for exact and partial matches. */
  public float f1Lenient;

  /** Number of exact matches. */
  public float correct;

  /** Number of instances incorretly with predicted label. */
  public float spurious;

  /** Number of positive instances missed by the system. */
  public float missing;

  /**
   * Number n for BDM computation, number of matches, instead of number of match
   * bdm score.
   */
  public float BDMn = 0;

  /** Number of only partial matches. */
  public float partialCor;

  /** Number of positive examples in key set. */
  private float keySize;

  /** Number of positive examples in the results. */
  private float resSize;

  /** Constructor. Set everything as zero. */
  public FMeasure() {
    precision = 0;
    recall = 0;
    f1 = 0;
    precisionLenient = 0;
    recallLenient = 0;
    f1Lenient = 0;
    correct = 0;
    spurious = 0;
    missing = 0;
    partialCor = 0;
    BDMn = 0;
  }

  /** Compute the F-measures from the numbers. */
  public void computeFmeasure() {
    keySize = correct + partialCor + spurious;
    resSize = correct + partialCor + missing;
    if(BDMn > 0) {
      keySize = BDMn + spurious;
      resSize = BDMn + missing;
    }
    if((keySize) == 0)
      precision = 0;
    else precision = (float)correct / keySize;
    if((resSize) == 0)
      recall = 0;
    else recall = (float)correct / resSize;
    if((precision + recall) == 0)
      f1 = 0;
    else f1 = 2 * precision * recall / (precision + recall);
    return;
  }

  /** Compute the lenient F-measures from the numbers. */
  public void computeFmeasureLenient() {
    keySize = correct + partialCor + spurious;
    resSize = correct + partialCor + missing;
    if(BDMn > 0) {
      keySize = BDMn + spurious;
      resSize = BDMn + missing;
    }
    if((keySize) == 0)
      precisionLenient = 0;
    else precisionLenient = (float)(correct + partialCor) / keySize;
    if((resSize) == 0)
      recallLenient = 0;
    else recallLenient = (float)(correct + partialCor) / resSize;
    if((precisionLenient + recallLenient) == 0)
      f1Lenient = 0;
    else f1Lenient =
            2 * precisionLenient * recallLenient
                    / (precisionLenient + recallLenient);
    return;
  }

  /** Accumulate the F-measure data for computing overall results. */
  public void add(FMeasure anotherMeasure) {
    this.correct += anotherMeasure.correct;
    this.partialCor += anotherMeasure.partialCor;
    this.missing += anotherMeasure.missing;
    this.spurious += anotherMeasure.spurious;
    this.precision += anotherMeasure.precision;
    this.recall += anotherMeasure.recall;
    this.f1 += anotherMeasure.f1;
    this.precisionLenient += anotherMeasure.precisionLenient;
    this.recallLenient += anotherMeasure.recallLenient;
    this.f1Lenient += anotherMeasure.f1Lenient;
    this.BDMn += anotherMeasure.BDMn;
    return;
  }

  /** Compute the macro averaged results. */
  public void macroAverage(int k) {
    if(k > 0) {
      this.correct /= k;
      this.partialCor /= k;
      this.missing /= k;
      this.spurious /= k;
      this.precision /= k;
      this.recall /= k;
      this.f1 /= k;
      this.precisionLenient /= k;
      this.recallLenient /= k;
      this.f1Lenient /= k;
      this.BDMn /= k;
    } else {
      System.out
              .println("Warning: the macro averaged F measure cannot be done because the number of pairs is less than 1.");
    }
    return;
  }

  /** Print out the results. */
  public String printResults() {
    StringBuffer logMessage = new StringBuffer();
    logMessage.append("  (correct, partial, spurious, missing)= (" + correct
            + ", " + partialCor + ", " + spurious + ", " + missing + ");  ");
    logMessage.append("(precision, recall, F1)= (" + precision + ", " + recall
            + ", " + f1 + ");  ");
    logMessage.append("Lenient: (" + (new Float(precisionLenient)) + ", "
            + recallLenient + ", " + f1Lenient + ")\n");
    return logMessage.toString();
  }
}