vpNoise.h

/****************************************************************************
 *
 * $Id: vpNoise.h 4056 2013-01-05 13:04:42Z fspindle $
 *
 * This file is part of the ViSP software.
 * Copyright (C) 2005 - 2013 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://www.irisa.fr/lagadic/visp/visp.html for more information.
 * 
 * This software was developed at:
 * INRIA Rennes - Bretagne Atlantique
 * Campus Universitaire de Beaulieu
 * 35042 Rennes Cedex
 * France
 * http://www.irisa.fr/lagadic
 *
 * 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 vpNoise_hh
#define vpNoise_hh


#include <visp/vpConfig.h>


class VISP_EXPORT vpUniRand
{


    /*unsigned*/ long    a  ;
    /*unsigned*/ long    m ; //2^31-1
    /*unsigned*/ long    q ; //integer part of m/a
    /*unsigned*/ 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();
    void init()
    {
        a = 16807 ;
        m = /*(unsigned long)*/2147483647 ; //2^31-1
        q = 127773 ; //integer part of m/a
        r = 2836 ;//r=m mod a
        //we use a normalizer > m to ensure ans will never be
        // 1 (it is the case if x = 739806647)
        normalizer = 2147484721.0 ;
    }

public:
    vpUniRand(const long seed = 0):x((seed)? seed : 739806647)
    {
        init() ;
    }
    double operator()() {return draw1();}

};

class vpGaussRand : public vpUniRand
{
    double mean;
    double sigma;

public:

    // Initialization
    vpGaussRand() {init();mean=0;sigma=0;x=739806647;}
    vpGaussRand(const double sqrtvariance,
            const double _mean,
            const long seed = 0):mean(_mean), sigma(sqrtvariance)
    {
        init() ;
        mean = 0 ;
        if (seed) x=seed; else x=739806647;
    }
    inline void setSigmaMean(const double _s, const double _m) {mean=_m;sigma=_s;}
    inline void seed(const long seed) {x=seed;}
    inline double operator()() {return sigma*gaussianDraw()+mean;}

private :
    double gaussianDraw();
};

#endif