PHG4PileupGenerator.cc

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#include "PHG4PileupGenerator.h"
 
#include <fun4all/Fun4AllReturnCodes.h>
 
#include <phool/PHCompositeNode.h>
#include <phool/PHRandomSeed.h>
 
#include <gsl/gsl_rng.h>
#include <gsl/gsl_randist.h>
 
using namespace std;
 
PHG4PileupGenerator::PHG4PileupGenerator(const string &name)
    : PHG4ParticleGeneratorBase(name),
      _generator(NULL),
      _min_integration_time(-1000.0),
      _max_integration_time(+1000.0),
      _collision_rate(100.0),
      _time_between_crossings(106.0),
      _ave_coll_per_crossing(1.0), // recalculated
      _min_crossing(0),            // recalculated
      _max_crossing(0) {           // recalculated
  return;
}
 
PHG4PileupGenerator::~PHG4PileupGenerator() {
  if (_generator) {
    delete _generator;
    _generator = NULL;
  }
}
 
int PHG4PileupGenerator::Init(PHCompositeNode *topNode) {
  if (!_generator) return Fun4AllReturnCodes::EVENT_OK;
  _generator->Init(topNode);
  return Fun4AllReturnCodes::EVENT_OK;
}
 
int PHG4PileupGenerator::InitRun(PHCompositeNode *topNode) {
 
  cout << "generator ptr: " << _generator << endl;
  
  if (!_generator) return Fun4AllReturnCodes::EVENT_OK;
 
  _generator->InitRun(topNode);
 
  _ave_coll_per_crossing = _collision_rate * _time_between_crossings * 1000.0 * 1e-9;
 
  _min_crossing = _min_integration_time / _time_between_crossings;
  _max_crossing = _max_integration_time / _time_between_crossings;
 
  return Fun4AllReturnCodes::EVENT_OK;
}
 
int PHG4PileupGenerator::process_event(PHCompositeNode *topNode) {
 
  if (!_generator) return Fun4AllReturnCodes::EVENT_OK;
 
  // toss multiple crossings all the way back
  for (int icrossing = _min_crossing; icrossing <= _max_crossing; ++icrossing) {
  
    double crossing_time = _time_between_crossings * icrossing;
 
    int ncollisions = gsl_ran_poisson(RandomGenerator,_ave_coll_per_crossing);
    if (icrossing == 0) --ncollisions;
 
    for (int icollision = 0; icollision < ncollisions; ++icollision) {
      _generator->set_t0(crossing_time);
      _generator->process_event(topNode);
    }
  }
   
  return Fun4AllReturnCodes::EVENT_OK;
}
 
int PHG4PileupGenerator::Reset(PHCompositeNode *topNode) {
  if (!_generator) return Fun4AllReturnCodes::EVENT_OK;
  _generator->Reset(topNode);
  return Fun4AllReturnCodes::EVENT_OK;
}
 
int PHG4PileupGenerator::ResetEvent(PHCompositeNode *topNode) {
  if (!_generator) return Fun4AllReturnCodes::EVENT_OK;
  _generator->ResetEvent(topNode);
  return Fun4AllReturnCodes::EVENT_OK;
}
 
int PHG4PileupGenerator::EndRun(const int runnumber) {
  if (!_generator) return Fun4AllReturnCodes::EVENT_OK;
  _generator->EndRun(runnumber);
  return Fun4AllReturnCodes::EVENT_OK;
}
 
int PHG4PileupGenerator::End(PHCompositeNode *topNode) {
  if (!_generator) return Fun4AllReturnCodes::EVENT_OK;
  _generator->End(topNode);
  return Fun4AllReturnCodes::EVENT_OK;
}