package de.lmu.ifi.dbs.elki.math.statistics.distribution;

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

 Copyright (C) 2012
 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/>.
 */

/**
 * Pseudo distribution, that has a unique constant value.
 * 
 * @author Erich Schubert
 */
public class ConstantDistribution implements DistributionWithRandom {
  /**
   * The constant
   */
  final double c;

  /**
   * Constructor.
   * 
   * @param c Constant
   */
  public ConstantDistribution(double c) {
    super();
    this.c = c;
  }

  @Override
  public double nextRandom() {
    return c;
  }

  @Override
  public double pdf(double val) {
    return (val == c) ? 1 : 0;
  }

  @Override
  public double cdf(double val) {
    return (val >= c) ? 1.0 : 0.0;
  }

  @Override
  public double quantile(double val) {
    return c;
  }
}