src/rng.h

/*
 *   See COPYING file distributed along with the psignifit package for
 *   the copyright and license terms
 */
#ifndef RNG_H
#define RNG_H

#include <cstdlib>
#include <cmath>
#include "errors.h"


class PsiRandom
{
        public:
                PsiRandom ( void ) {}
                double rngcall ( void );
                virtual double draw ( void ) { throw NotImplementedError(); }
                virtual PsiRandom * clone ( void ) const {throw NotImplementedError(); }
};

class GaussRandom : public PsiRandom
{
        private:
                double mu;
                double sigma;
                bool good;
                double x1;
                double x2;
                double w;
                double y;
        public:
                GaussRandom ( double mean=0, double standarddeviation=1 ) : mu ( mean ), sigma ( standarddeviation ), good ( false ) {}
                double draw ( void );              
                PsiRandom * clone ( void ) const { return new GaussRandom(*this); }
};

class UniformRandom : public PsiRandom
{
        private:
                double lower;
                double upper;
        public:
                UniformRandom ( double low=0, double up=1 ) : lower(low), upper(up) {}
                double draw ( void ) { return  (upper-lower)*rngcall()+lower; }
                PsiRandom * clone ( void ) const { return new UniformRandom(*this); }
};

class BinomialRandom : public PsiRandom
{
        private:
                int n;
                double p;
        public:
                BinomialRandom ( int number, double probability ) : n(number), p(probability) {}
                double draw ( void );
                void setprm ( int number, double probability ) { n = number; p = probability; }
                PsiRandom * clone ( void ) const { return new BinomialRandom(*this); }
};

class GammaRandom : public PsiRandom
{
        private:
                double k;
                double theta;
                GaussRandom grng;
        public:
                GammaRandom ( double shape, double scale ) : k (shape), theta(scale), grng() {}
                double draw ( void );              
                PsiRandom * clone ( void ) const { return new GammaRandom(*this); }
};

class BetaRandom : public PsiRandom
{
        private:
                double alpha;
                double beta;
                GammaRandom grnga;
                GammaRandom grngb;
        public:
                BetaRandom ( double alpha, double beta ) : alpha(alpha), beta(beta), grnga (alpha, 1), grngb (beta, 1) {}
                double draw ( void );              
                PsiRandom * clone ( void ) const { return new BetaRandom(*this); }
};


void setSeed(long int seedval);

#endif