Difference between revisions of "Analysis FAQ"

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(Histogramming)
(Histogramming)
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//If not already present, include the appropriate ROOT header file in your processor header file:
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#include "TH1D.h" //1 dimensional ("1") histogram containing doubles ("D")
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//Define your histogram in your processor class definition:
 
//Define your histogram in your processor class definition:
 
TH1D* dMyHist;
 
TH1D* dMyHist;

Revision as of 13:34, 18 July 2014

Neutrals

  • Given a DNeutralParticleHypothesis or DNeutralShower object, how do I get the FCAL/BCAL shower objects?
    • Answer: By calling the inherited JObject::GetSingle() function:
//given a hypothesis, get the neutral shower:
const DNeutralShower* locNeutralShower = NULL;
locNeutralParticleHypothesis->GetSingle(locNeutralShower);
 
//given a neutral shower, get the BCAL shower:
const DFCALShower* locFCALShower = NULL;
if(locNeutralShower->dDetectorSystem == SYS_FCAL)
   locNeutralShower->GetSingle(locFCALShower);
 
//given a neutral shower, get the FCAL shower:
const DBCALShower* locBCALShower = NULL;
if(locNeutralShower->dDetectorSystem == SYS_BCAL)
   locNeutralShower->GetSingle(locBCALShower);

Histogramming

  • How do I manually create and fill a histogram in my plugin's processor in a way that is thread-safe?
//If not already present, include the appropriate ROOT header file in your processor header file:
#include "TH1D.h" //1 dimensional ("1") histogram containing doubles ("D")
 
//Define your histogram in your processor class definition:
TH1D* dMyHist;
 
//Create your histogram in your processor init() method:
   //Note that you do not need a ROOT lock here, since the init() method of event processors is only called by one of the threads. 
   //If you were doing this in a factory, you would need a ROOT lock here. 
dMyHist = new TH1D("HistName", "Hist Title;X-axis Title;Y-axis Title", 100, 0.0, 1.0); //100 bins from 0 to 1
 
//Fill the histogram in your processor evnt() method, but within a ROOT lock:
double locValue = 1.0;
japp->RootWriteLock(); //ACQUIRE ROOT LOCK!!
{
   dMyHist->Fill(locValue);
}
japp->RootUnLock(); //RELEASE ROOT LOCK!!
 
//The histogram is automatically saved to hd_root.root, or the file you specified with "-o" on the command line.

Cuts

  • How do I place a cut prior to kinematic fitting?
    • Answer: Add an analysis action to the DReaction that performs the cut. It should be added prior to any action that uses the kinematic fit results. If no action uses the fit results, then it can be added anywhere.
   //place cut on pi0 invariant mass (assuming a Pi0 decay step is defined in your DReaction): 
      //the false means "used measured data" as opposed to kinfit data
      //0.04 and 0.24 specify the minimum and maximum invariant mass
   locReaction->Add_AnalysisAction(new DCutAction_InvariantMass(locReaction, Pi0, false, 0.04, 0.24)); //does not require kinfit results
   locReaction->Add_AnalysisAction(new DHistogramAction_KinFitResults(locReaction, 0.05)); //requires kinfit results
   //Thus, the kinematic fit is performed between execution of these actions. If a combo fails a cut prior to the kinfit, then it is not performed for that combo.