// configures a TPythia6 class

// usage: o2sim -g external --configKeyValues 'GeneratorExternal.fileName=pythia6.C;GeneratorExternal.funcName="pythia6(14000., "pythia.settings")"'

/// \author R+Preghenella - October 2018

#if !defined(__CLING__) || defined(__ROOTCLING__)

#include "TPythia6.h"

#include "FairGenerator.h"

#include "Generators/GeneratorTGenerator.h"

#include <fstream>

#include <iostream>

#endif

R__LOAD_LIBRARY(libpythia6)

void configure(TPythia6* py6, const char* params);

FairGenerator*

pythia6(double energy = 14000., const char* params = nullptr)

{

// instance and configure Pythia6

auto py6 = TPythia6::Instance();

if (params)

configure(py6, params);

py6->Initialize("CMS", "p", "p", energy);

// instance and configure TGenerator interface

auto tgen = new o2::eventgen::GeneratorTGenerator();

tgen->setMomentumUnit(1.); // [GeV/c]

tgen->setEnergyUnit(1.); // [GeV/c]

tgen->setPositionUnit(0.1); // [cm]

tgen->setTimeUnit(3.3356410e-12); // [s]

tgen->setTGenerator(py6);

return tgen;

}

void configure(TPythia6* py6, const char* params)

{

std::ifstream file(params);

if (!file.is_open()) {

std::cerr << "Cannot open configuration file: " << params << std::endl;

return;

};

std::string line, command;

while (std::getline(file, line)) {

/** remove comments **/

command = line.substr(0, line.find_first_of("#"));

if (command.length() == 0)

continue;

py6->Pygive(command.c_str());

}

file.close();

}