MCTruthParticleList.h File Reference

Particle list in DetSim contains Monte Carlo particle information. More...

#include "nusimdata/SimulationBase/MCParticle.h"
#include <memory>
#include <ostream>
#include <map>
#include <cstdlib>

Go to the source code of this file.

Classes
class	truth::MCTruthParticleList
struct	truth::MCTruthParticleList::archived_info_type

Namespaces
	truth
	Monte Carlo Simulation.

Detailed Description

Particle list in DetSim contains Monte Carlo particle information.

Version

Id:

MCTruthParticleList.h,v 1.13 2010/05/13 16:12:20 seligman Exp

Author

selig.nosp@m.man@.nosp@m.nevis.nosp@m..col.nosp@m.umbia.nosp@m..edu

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*** This class has been lifted from nutools and modified so that it *** does NOT take ownwership of the MCParticles that are added to it *** so we can avoid duplicating them

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A container for particles generated during an event simulation. It acts like a map<int,Particle*> but with additional features:

• A method Cut(double) that will remove all particles with energy less than the argument.
• Methods TrackId(int) and Particle(int) for those who are unfamiliar with the concepts associated with STL maps: truth::MCTruthParticleList* MCTruthParticleList = // ...; int numberOfParticles = MCTruthParticleList->size(); for (int i=0; i<numberOfParticles; ++i) { int trackID = MCTruthParticleList->TrackId(i); simb::MCParticle* particle = MCTruthParticleList->Particle(i); } The STL equivalent to the above statements (more efficient): truth::MCTruthParticleList* MCTruthParticleList = // ...; for ( auto i = MCTruthParticleList->begin(); i != MCTruthParticleList->end(); ++i ) { const simb::MCParticle* particle = (i).second; int trackID = particle->TrackId(); // or... int trackID = (*i).first; } or, more compact: truth::MCTruthParticleList MCTruthParticleList = // ...; for ( const auto& i: MCTruthParticleList) { const simb::MCParticle particle = i.second; int trackID = particle->TrackId(); // or... int trackID = i.first; } If looping over all the particles, do prefer the second and third forms, since the first one is unacceptably inefficient for large events.

• Methods to access the list of primary particles in the event: truth::MCTruthParticleList MCTruthParticleList = // ...; int numberOfPrimaries = MCTruthParticleList->NumberOfPrimaries(); for ( int i = 0; i != numberOfPrimaries; ++i ) { simb::MCParticle* particle = MCTruthParticleList->Primary(i); ... } There's also a simple test: int trackID = // ...; if ( MCTruthParticleList->IsPrimary(trackID) ) {...}

  (Aside: note that MCTruthParticleList[i] does NOT give you the "i-th" particle in the list; it gives you the particle whose trackID is "i".) Also this form becomes unacceptably inefficient when looping over all the particles in a crowded event: prefer to do a bit more of typing as: truth::MCTruthParticleList* MCTruthParticleList = // ...; for ( const auto& i: MCTruthParticleList) { int trackID = i.first; if (!MCTruthParticleList->IsPrimary(trackID)) continue; const simb::MCParticle primary = i.second; // ... }

Definition in file MCTruthParticleList.h.