db/dcd/ThermPtnSampler_8h_source.html

#ifndef THERMPTNSAMPLER_H

#define THERMPTNSAMPLER_H


#include "JetScapeLogger.h"

#include <vector>

#include <random>


using namespace Jetscape;


class ThermalPartonSampler

{

 public:

        //constructor - initializes variables and random number generator

        ThermalPartonSampler(unsigned int ran_seed);


        //sampler - samples thermal partons (u,d,s) from brick or 2+1d / 3+1d hydro

        void samplebrick();

        void sample_2p1d(double eta_max);

        void sample_3p1d(bool Cartesian_hydro=false);


        //to load a hypersurface

        void set_hypersurface(std::vector<std::vector<double>> surf_in){surface = surf_in;}


        //setters for params

        void brick_length_width(double len_bri, double wid_bri){L = 2.*len_bri + 4.; W = 2.*wid_bri + 4.; Time = len_bri;} // +4 gives 2fm additional brick in each direction

        void brick_flow(double vx_in, double vy_in, double vz_in){Vx = vx_in; Vy = vy_in; Vz = vz_in;}

        void brick_Tc(double brick_Tc){T = brick_Tc/GEVFM;}


        //getters for thermal partons

        int nTot(         ){return Plist.size();}

        int th_Evnum(int i){return (int)Plist[i][0];}

        int th_pid(  int i){return (int)Plist[i][1];}

        int th_orig( int i){return (int)Plist[i][2];}

        int th_stat( int i){return (int)Plist[i][11];}

        double th_px(int i){return      Plist[i][3];}

        double th_py(int i){return      Plist[i][4];}

        double th_pz(int i){return      Plist[i][5];}

        double th_e( int i){return      Plist[i][6];}

        double th_x( int i){return      Plist[i][7];}

        double th_y( int i){return      Plist[i][8];}

        double th_z( int i){return      Plist[i][9];}

        double th_t( int i){return      Plist[i][10];}

        int th_nL(){return num_ud;}

        int th_nS(){return num_s;}


 private:


        //thermal parton list

        std::vector<std::vector<double>> Plist; // List of particles ( [0]->event number; [1]->particle ID; [2]->origin; [3-6]->Px,Py,Pz,E; [7-10]->x,y,z,t; [11]->Particle Status )

                                                                                        // Same format as in shower data, event number is always 1, origin is always 0, particle status is always 0 (indicates a thermal quark)


        // Functions

        bool SplitSort (double goal, int floor, int ceiling, int quark);

        void MCSampler(double Temp, int quark);                                 //Samples momentum distribution, redefines NewP, NewX, NewY, NewZ variables - momentum in rest frame

        double FermiPDF (double Pc, double Mc, double Tc, double muc);          //Gives form of Fermi-Dirac distribution (no normalization factors!). Mu is currently given by 0 everywhere

        void CDFGenerator(double Temp, double M, int quark);                            //generates cumulative distribution in thermal rest frame "quark" is 1 for light and 2 for strange


        // random number handling

        std::mt19937_64 rng_engine; //RNG - Mersenne Twist - 64 bit

        std::uniform_real_distribution<double> distribution{0.0, 1.0}; // Uniform distribution between 0 and 1

        // Function to generate a random number between 0 and 1

    double ran() {return distribution(rng_engine);}

        // Function to get the random number generator

    std::mt19937_64& getRandomGenerator() {return rng_engine;}


        // Static parameters, do not change

        const double PI = 3.141592653589793;

        double muPi0 = 0.;

        const double GEVFM = 0.197327053;


        // Adjustable parameters

        double xmq, xms, T, NUMSTEP;

        double CellDX, CellDY, CellDZ, CellDT;


        // Gaussian weights and abscissa (50 pt)

        // Used in numeric integration

        int GPoints = 50;               // Amount of Gaussian points for quadrature

        double GWeight[50];             // Gaussian weights for integration

        double GAbs[50];                // Gaussian abscissas for integration


        // Flags

        bool SetNum, SetNumLight, SetNumStrange, ShuffleList;


        // Global vars between functions

        double NewX, NewY, NewZ, NewP;

        int num_ud, num_s;

        std::vector<std::vector<double>> CDFTabLight;   // Cumulative distribution for thermal light quarks

        std::vector<std::vector<double>> CDFTabStrange; // Cumulative distribution for s quarks


        // Brick info

        //L is the length of the brick sampled for thermal partons

        //W is the width of the face of the brick - should be scaled somewhat against L

        //Vx,Vy,Vz is a flow given to the brick

        double L, W, Time, Vx, Vy, Vz;


        // HyperSurface

        std::vector<std::vector<double>> surface;

};


#endif // THERMPTNSAMPLER_H