gsl_binomial_randomdev.h

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/*
 *  gsl_binomial_randomdev.h
 *
 *  This file is part of NEST.
 *
 *  Copyright (C) 2004 The NEST Initiative
 *
 *  NEST 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.
 *
 *  NEST 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 NEST.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "config.h"

#ifndef GSL_BINOMIAL_RANDOMDEV_H
#define GSL_BINOMIAL_RANDOMDEV_H

#include "randomgen.h"
#include "randomdev.h"
#include "lockptr.h"
#include "dictdatum.h"
#include "gslrandomgen.h"

#ifdef HAVE_GSL

#include <gsl/gsl_rng.h>
#include <gsl/gsl_randist.h>


/*BeginDocumentation
Name: rdevdict::gsl_binomial - GSL binomial random deviate generator
Description:
This function returns a random integer from the binomial distribution,
the number of successes in n independent trials with probability
p. The probability distribution for binomial variates is,

   p(k) = (n! / k!(n-k)!) p^k (1-p)^(n-k)  , 0<=k<=n, n>0

Please note that the RNG used to initialize gsl_binomial has to be
from the GSL (prefixed gsl_ in rngdict)

Parameters:
   p - probability of success in a single trial (double)
   n - number of trials (positive integer)

SeeAlso: CreateRDV, RandomArray, rdevdict
Author: Jochen Martin Eppler
*/


namespace librandom {

class GSL_BinomialRandomDev : public RandomDev
  {
  public:
    // accept only lockPTRs for initialization,
    // otherwise creation of a lock ptr would
    // occur as side effect---might be unhealthy
    GSL_BinomialRandomDev(RngPtr, double p_s = 0.5, unsigned int n_s=1);
    GSL_BinomialRandomDev(double p_s = 0.5, unsigned int n_s=1);

    void   set_p_n   (double, unsigned int);
    void   set_p     (double);                 
    void   set_n     (unsigned int);           

    using RandomDev::operator();
    using RandomDev::ldev;

    long ldev();         
    long ldev(RngPtr) const;   
    bool has_ldev() const { return true; }

    double operator()(RngPtr) const;     

    void set_status(const DictionaryDatum&);

    void get_status(DictionaryDatum&) const;

  private:
    double p_;                  
    unsigned int n_;            

    gsl_rng *rng_;
  };

  inline
  double GSL_BinomialRandomDev::operator()(RngPtr rthrd) const
  {
    return static_cast<double>(ldev(rthrd));
  }

}

#endif

#endif