package de.lmu.ifi.dbs.elki.distance.distancefunction;

/*
 This file is part of ELKI:
 Environment for Developing KDD-Applications Supported by Index-Structures

 Copyright (C) 2015
 Ludwig-Maximilians-Universität München
 Lehr- und Forschungseinheit für Datenbanksysteme
 ELKI Development Team

 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU Affero General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Affero General Public License for more details.

 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

import de.lmu.ifi.dbs.elki.data.NumberVector;
import de.lmu.ifi.dbs.elki.data.spatial.SpatialComparable;
import de.lmu.ifi.dbs.elki.utilities.documentation.Reference;
import de.lmu.ifi.dbs.elki.utilities.optionhandling.AbstractParameterizer;

/**
 * Kulczynski similarity 1, in distance form.
 * 
 * Reference:
 * <p>
 * M.-M. Deza and E. Deza<br />
 * Dictionary of distances
 * </p>
 * 
 * @author Erich Schubert
 * @since 0.4.0
 */
@Reference(authors = "M.-M. Deza and E. Deza", title = "Dictionary of distances", booktitle = "Dictionary of distances")
public class Kulczynski1DistanceFunction extends AbstractSpatialDistanceFunction {
  /**
   * Static instance.
   */
  public static final Kulczynski1DistanceFunction STATIC = new Kulczynski1DistanceFunction();

  /**
   * Constructor.
   * 
   * @deprecated Use {@link #STATIC} instance instead.
   */
  @Deprecated
  public Kulczynski1DistanceFunction() {
    super();
  }

  @Override
  public double distance(NumberVector v1, NumberVector v2) {
    final int dim = dimensionality(v1, v2);
    double sumdiff = 0., summin = 0.;
    for (int d = 0; d < dim; d++) {
      final double xd = v1.doubleValue(d), yd = v2.doubleValue(d);
      sumdiff += Math.abs(xd - yd);
      summin += Math.min(xd, yd);
    }
    return sumdiff / summin;
  }

  @Override
  public double minDist(SpatialComparable mbr1, SpatialComparable mbr2) {
    final int dim = dimensionality(mbr1, mbr2);
    double sumdiff = 0., summin = 0.;
    for (int d = 0; d < dim; d++) {
      final double min1 = mbr1.getMin(d), max1 = mbr1.getMax(d);
      final double min2 = mbr2.getMin(d), max2 = mbr2.getMax(d);
      if (max1 < min2) {
        sumdiff += min2 - max1;
      } else if (min1 > max2) {
        sumdiff += min1 - max2;
      } else {
        // Minimum difference is 0
      }
      summin += Math.min(min1, min2);
    }
    return sumdiff / summin;
  }

  /**
   * Parameterization class.
   * 
   * @author Erich Schubert
   * 
   * @apiviz.exclude
   */
  public static class Parameterizer extends AbstractParameterizer {
    @Override
    protected Kulczynski1DistanceFunction makeInstance() {
      return Kulczynski1DistanceFunction.STATIC;
    }
  }
}
