/**
 * ConstantDensityBoundedSet.java
 * @author Fabio G. Cozman 
 * Copyright 1996 - 1999, Fabio G. Cozman,
 *          Carnergie Mellon University, Universidade de Sao Paulo
 * fgcozman@usp.br, http://www.cs.cmu.edu/~fgcozman/home.html
 *
 * The JavaBayes distribution is free software; you can
 * redistribute it and/or modify it under the terms of the GNU General
 * Public License as published by the Free Software Foundation (either
 * version 2 of the License or, at your option, any later version), 
 * provided that this notice and the name of the author appear in all 
 * copies. Upon request to the author, some of the packages in the 
 * JavaBayes distribution can be licensed under the GNU Lesser General
 * Public License as published by the Free Software Foundation (either
 * version 2 of the License, or (at your option) any later version).
 * If you're using the software, please notify fgcozman@usp.br so
 * that you can receive updates and patches. JavaBayes is distributed
 * "as is", 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 General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with the JavaBayes distribution. If not, write to the Free
 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

package CredalSets;

import BayesianNetworks.*;

public class ConstantDensityBoundedSet
       extends TwoMonotoneCapacity {
  /**
   * The "size" of the density bounded class.
   */
  private double k;

  /**
   * Constructor for a ConstantDensityBoundedSet given a 
   * ProbabilityFunction object and given constant.
   */
  public ConstantDensityBoundedSet(ProbabilityFunction pf, double kk) {
     super(pf);
     k = kk;
     if (k <= 0.0) k = 1.0;
     else {
       	if (k < 1.0) k = 1.0/k;
     }
  }

  /**
   * Obtain the lower probability of an event given the base    
   * probability for the event.                                 
   */
  public double get_lower_probability_from_base(double p) {
    return( Math.max( p/k, 1 - k * ( 1 - p ) ) );
  }

  /**
   * Obtain the upper probability of an event given the base    
   * probability for the event.                                 
   */
  public double get_upper_probability_from_base(double p) {
    return( Math.min( k * p, 1 - (1-p)/k ) );
  }

  /**
   * Get a base probability value for an atom. 
   */
  public double get_atom_probability(int index) {
    return( values[index] );
  }
}