vpUniRand.h

/****************************************************************************
 *
 * This file is part of the ViSP software.
 * Copyright (C) 2005 - 2017 by Inria. All rights reserved.
 *
 * This software is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * ("GPL") version 2 as published by the Free Software Foundation.
 * See the file LICENSE.txt at the root directory of this source
 * distribution for additional information about the GNU GPL.
 *
 * For using ViSP with software that can not be combined with the GNU
 * GPL, please contact Inria about acquiring a ViSP Professional
 * Edition License.
 *
 * See http://visp.inria.fr for more information.
 *
 * This software was developed at:
 * Inria Rennes - Bretagne Atlantique
 * Campus Universitaire de Beaulieu
 * 35042 Rennes Cedex
 * France
 *
 * If you have questions regarding the use of this file, please contact
 * Inria at visp@inria.fr
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Description:
 * Generation of random number with uniform and normal probability density.
 *
 * Authors:
 * Eric Marchand
 *
 *****************************************************************************/

#ifndef vpUniRand_hh
#define vpUniRand_hh

#include <visp3/core/vpConfig.h>

class VISP_EXPORT vpUniRand
{
  long    a;
  long    m; //2^31-1
  long    q; //integer part of m/a
  long    r;//r=m mod a
  double normalizer; //we use a normalizer > m to ensure ans will never be 1 (it is the case if x = 739806647)

private:
  void draw0();
protected:
  long x;
  double draw1();

public:
  vpUniRand(const long seed = 0)
    : a(16807), m(2147483647), q(127773), r(2836), normalizer(2147484721.0), x((seed)? seed : 739806647)
  {}

  virtual ~vpUniRand() {};

  double operator()() {
    return draw1();
  }
};

#endif