DBeamPhoton_factory_TAGGEDMCGEN.cc

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// $Id$
//
//    File: DBeamPhoton_factory_TAGGEDMCGEN.cc
// Created: Thu Dec  3 17:27:55 EST 2009
// Creator: staylor (on Linux ifarml6 2.6.18-128.el5 x86_64)
//

#include <iostream>
#include <iomanip>
using namespace std;

#include "DBeamPhoton_factory_TAGGEDMCGEN.h"
using namespace jana;

//------------------
// evnt
//------------------
jerror_t DBeamPhoton_factory_TAGGEDMCGEN::evnt(jana::JEventLoop *locEventLoop, uint64_t eventnumber)
{
   _data.clear();

   //Check if MC
   vector<const DMCReaction*> locMCReactions;
   locEventLoop->Get(locMCReactions);
   if(locMCReactions.empty())
      return NOERROR; //Not a thrown event

   //Get the MCGEN beam
   const DBeamPhoton* locMCGenBeam;
   locEventLoop->GetSingle(locMCGenBeam, "MCGEN");

   //See if it was tagged
   auto locSystem = locMCGenBeam->dSystem;
   if(locSystem == SYS_NULL)
      return NOERROR; //Nope, no objects to create

   //Get reconstructed beam photons
   vector<const DBeamPhoton*> locBeamPhotons;
   locEventLoop->Get(locBeamPhotons);

   //Loop over beam photons
   double locBestDeltaT = 9.9E9;
   const DBeamPhoton* locBestPhoton = nullptr;
   for(auto& locBeamPhoton : locBeamPhotons)
   {
      if(locBeamPhoton->dSystem != locSystem)
         continue;
      if(locBeamPhoton->dCounter != locMCGenBeam->dCounter)
         continue;

      auto locDeltaT = fabs(locMCGenBeam->time() - locBeamPhoton->time());
      if(locDeltaT >= locBestDeltaT)
         continue;
      locBestDeltaT = locDeltaT;
      locBestPhoton = locBeamPhoton;
   }

   if(locBestPhoton == nullptr)
      return NOERROR; //Uh oh.  Shouldn't be possible. 

   _data.push_back(new DBeamPhoton(*locBestPhoton));
   return NOERROR;
}