reco::Candidate: a generic reconstructed particle candidates. It adds to reco::Particle interface for navigation among constituents. Utilities to extract components from a reco::Candidate avoiding explicit dynamic_cast are provided. A tag struct can be used as optional second template parameter to disambiguate between more components in a Candidate of the same type. The following example shows how to extract references to a reco::Track or reco::Muon. The following syntaxes are all equivalent:
const Candidate & cand = ...;
TrackRef track1 = c.get<TrackRef>( c );
TrackRef track2 = get<TrackRef>( c );
TrackRef track3 = component<TrackRef>::get( c );
It is possible to access different types of components, but you have to get sure to include the header files of the concrete candidate subclass in order to define the proper template specialization.
const Candidate & c = ...;
TrackRef track = c.get<TrackRef>();
SuperClusterRef cluster = c.get<SuperClusterRef>();
const Candidate & g = ...;
const HepMC::GenParticle * gen = g.get<const HepMC::GenParticle *>();
In case of multiple components of the same type, it is possible to specify an extra "tag" to disentangle the ambiguity. For instance:
const Candidate & muon = ...;
// tracker fit: default
TrackRef trackerFit = muon.get<TrackRef>();
// stand alone muon fit
TrackRef standAloneMuFit = muon.get<TrackRef, StandAloneMuonTag>();
// combined muon + tracker fit
TrackRef combinedFit = muon.get<TrackRef, CombinedMuonTag>();
1.5.4