asogaard / analysistools

Various tools for easily implementing modular HEP analyses (object definition, cutflow, bookkeeping, plotting, etc.).

AnalysisTools

A small package, providing various classes for easily implementing a modular analysis, including object definition, event selection, cutflows, and distributions.

Provides classes for selectable entities (PhysicsObject, Event), selection operations (Operation, Cut), types of selection (Selection, EventSelection, ObjectDefinition), analyses (Analysis), and various other helper classes (Range, PlotMacro). The only external dependency is ROOT.

Usage

In order to use the AnalysisTools package, do as follows.

$ cd /my/path/
$ git clone https://github.com/asogaard/AnalysisTools.git
$ cd AnalysisTools
$ source setup.sh
$ make

The package comes bundled with a few use examples, located in the Root directory.

Example

A very simple analysis can be implemented as follows:

 // Stuff that goes into the analysis.
// -------------------------------------------------------------------

vector<TLorentzVector>* electrons = ...;
vector<TLorentzVector>* muons     = ...;

vector<bool>* el_id_medium = ...;
vector<bool>* mu_id_medium = ...;


 // Main analysis.
// -------------------------------------------------------------------

Analysis analysis ("MyAnalysis");
analysis.openOutput("output.root");


 // Object definitions.
// -------------------------------------------------------------------

// -- Electrons
ObjectDefinition<TLorentzVector> ElectronObjdef ("Electrons");
ElectronObjdef.setInput(electrons);
ElectronObjdef.addInfo("id_medium", el_id_medium);

// * pT
Cut<PhysicsObject> el_pT ("pT");
el_pT.setFunction( [](const PhysicsObject& p) { return p.Pt() / 1000.; } );
el_pT.setRange(20., inf);
ElectronObjdef.addCut(el_pT);

// * ID (medium).
Cut<PhysicsObject> el_ID ("MediumID");
el_ID.setFunction( [](const PhysicsObject& p) { return p.info("id_medium"); } );
ElectronObjdef.addCut(el_ID);

// -- Muons
ObjectDefinition<TLorentzVector> MuonObjdef ("Muons");
MuonObjdef.setInput(muons);
MuonObjdef.addInfo("id_medium", mu_id_medium);

// * pT
Cut<PhysicsObject> mu_pT ("pT");
mu_pT.setFunction( [](const PhysicsObject& p) { return p.Pt() / 1000.; } );
mu_pT.setRange(20., inf);
MuonObjdef.addCut(mu_pT);

// * ID (medium).
Cut<PhysicsObject> mu_ID ("MediumID");
mu_ID.setFunction( [](const PhysicsObject& p) { return p.info("id_medium"); } );
MuonObjdef.addCut(mu_ID);

// -- Output
PhysicsObjects* SelectedElectrons = ElectronObjdef.result("Nominal"); /* Default category name. */
PhysicsObjects* SelectedMuons     = MuonObjdef    .result();


 // Event selection.
// -------------------------------------------------------------------

EventSelection eventSelection ("EventSelection");

eventSelection.addCollection("Electrons", SelectedElectrons);
eventSelection.addCollection("Muons",     SelectedMuons);

// * Lepton count
Cut<Event> event_Nleptons ("Nleptons");
event_Nleptons.setFunction( [](const Event& e) { return e.collection("Electrons")->size() + e.collection("Muons")->size(); });
event_Nleptons.addRange(2);
eventSelection.addCut(event_Nleptons);


 // Adding selections.
// -------------------------------------------------------------------

analysis.addSelection(&ElectronObjdef);
analysis.addSelection(&MuonObjdef);
analysis.addSelection(&eventSelection);


 // Run analysis.
// -------------------------------------------------------------------

for (unsigned int iEvent = 0; iEvent < nEvents; iEvent++) {

    /* Fill input collections, e.g. with TTree::GetEvent(int). */

    analysis.run();

}

analysis.save();

Here we select a subset of leptons, from an input collection, and require that the event has exactly two leptons. The AnalysisTools::Analysis object then writes the approriate distribution and cutflow to the ROOT file specificied at the top. Optionally, one can use the void AnalysisTools::Analysis::addTree(const string&), TTree* AnalysisTools::Analysis::tree(), and void AnalysisTools::Analysis::writeTree() to write e.g. the selected leptons to the output file as well.

Comments

For running, remember to the the LD_LIBRARY_PATH to include the package library directory, i.e.:

$ export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/my/path/AnalysisTools/lib

Similarly, you should make sure that you compiler supports C++11 (GCC version >= 4.7.0). However, both of these things should be checked/taken care of by the setup.sh script.