source: trunk/yat/random/random.cc @ 706

// $Id: random.cc 706 2006-12-19 08:59:19Z jari $

/*
  Copyright (C) 2005, 2006 Jari Häkkinen, Peter Johansson

  This file is part of the yat library, http://lev.thep.lu.se/trac/yat

  The yat library 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.

  The yat library 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
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  02111-1307, USA.
*/

#include "random.h"
#include "yat/statistics/Histogram.h"

#include <fstream>
#include <iostream>

namespace theplu {
namespace yat {
namespace random {

  RNG* RNG::instance_ = NULL;


  RNG::RNG(void)
  {
    gsl_rng_env_setup();  // support rng/seed changes through environment vars
    rng_ = gsl_rng_alloc(gsl_rng_default);  // Memory is allocated here!
  }


  RNG::~RNG(void)
  {
    gsl_rng_free(rng_);
    rng_=NULL;
    delete instance_;
  }

  
  u_long RNG::seed_from_devurandom(void)
  {
    u_char ulongsize=sizeof(u_long);
    char* buffer=new char[ulongsize];
    std::ifstream is("/dev/urandom");
    is.read(buffer,ulongsize);
    is.close();
    u_long s=0;
    for (u_int i=0; i<ulongsize; i++) {
      u_char ch=buffer[i];
      s+=ch<<((ulongsize-1-i)*8);
    }
    seed(s);
    return s;
  }


  int RNG::set_state(const RNG_state& state)
  {
    return gsl_rng_memcpy(rng_, state.rng());
  }


  RNG_state::RNG_state(const RNG* rng)
  {
    rng_ = gsl_rng_clone(rng->rng()); 
  }
  

  RNG_state::~RNG_state(void)
  {
    gsl_rng_free(rng_);
    rng_=NULL;
  }

  // --------------------- Discrete distribtuions ---------------------

  Discrete::Discrete(void)
    : rng_(RNG::instance())
  {
  }

  
  Discrete::~Discrete(void)
  {
  }


  DiscreteGeneral::DiscreteGeneral(const statistics::Histogram& hist)
  {
    double* p = new double[ hist.nof_bins() ];
    for (size_t i=0; i<hist.nof_bins(); i++) 
      p[ i ] = hist[i];
    gen_ = gsl_ran_discrete_preproc( hist.nof_bins(), p );
    delete p;
  }


  DiscreteGeneral::~DiscreteGeneral(void)
  {
    if (gen_)
      gsl_ran_discrete_free( gen_ );
    gen_ = NULL;
  }


  Poisson::Poisson(const double m)
    : m_(m)
  {
  }

  // --------------------- Continuous distribtuions ---------------------

  Continuous::Continuous(void)
    : rng_(RNG::instance())
  {
  }


  Continuous::~Continuous(void)
  {
  }


  ContinuousGeneral::ContinuousGeneral(const statistics::Histogram& hist)
    : discrete_(DiscreteGeneral(hist)), hist_(hist)
  {
  }


  Exponential::Exponential(const double m)
    : m_(m)
  {
  }


  Gaussian::Gaussian(const double s, const double m)
    : m_(m), s_(s)
  {
  }

}}} // of namespace random, yat, and theplu